A flaw was found in OpenSSH. This vulnerability, a heap out-of-bounds read, occurs during the cleanup of GSSAPI (Generic Security Service Application Programming Interface) indicators when a trailing NULL termination is missing in the auth-indicators array. A remote attacker, under specific configurations involving GSSAPI authentication and a Kerberos environment, could exploit this to cause the SSH authentication path to crash or abort. This leads to a denial of service (DoS), impacting the availability of the SSH service.

A flaw was found in tar. A remote attacker could exploit this vulnerability by crafting a malicious archive, leading to hidden file injection with fully attacker-controlled content. This bypasses pre-extraction inspection mechanisms, potentially allowing an attacker to introduce malicious files onto a system without detection.

A flaw was found in libssh automatic certificate-based public key authentication. In sshuserauthpublickeyauto() in src/auth.c, the iterator over certificate candidates was not advanced correctly when configured certificates were missing or repeatedly rejected by the server. Under specific non-default certificate configurations, this could cause the client to restart the same authentication attempts indefinitely, leading to denial of service.

A flaw was found in libssh in the server-side GSSAPI Curve25519 key exchange path in src/kex-gss.c. In sshservergsskexprocessinit(), a client-controlled SSH string is unpacked into clientpubkey and then copied with memcpy(..., CURVE25519PUBKEYSIZE) without validating sshstringlen(clientpubkey). A remote unauthenticated client can send a short public key in SSHMSGKEXGSSINIT and trigger an out-of-bounds heap read during handshake processing, disclosing small amounts of adjacent server memory.

A flaw was found in libssh server-side SFTP directory listing. In processreaddir() in src/sftpserver.c, the server allocates a fixed stack buffer as char longname[MAXLONGNAMELEN] and passes attacker-controlled directory entry names into readdirlongname(). In the pre-patch implementation, readdirlongname() appends metadata and the filename into zlongname with repeated unbounded strcat() calls. Because zlongname points at the caller-owned fixed stack buffer, sufficiently long filenames in an attacker-controlled directory can overflow that stack buffer during SSHFXPREADDIR processing, leading to crashes and possible code execution on the server.

A flaw was found in libkcapi. A local attacker can influence an application that uses the Asynchronous Input/Output (AIO) interface. By reusing an AIO-enabled handle after a prior completion error, the kcapiaioreadall() function can enter a non-terminating wait loop. This can lead to a persistent denial of service, making the affected application or thread unresponsive.

AIONLYREPORT package: libkcapi-1.5.0-3.el10 ------ Summary: Memory Corruption via Uncanceled AIO Requests on Error: libkcapi's one-shot AIO path can return an error before all submitted IOCBs are drained, allowing later kernel writes into caller-owned output buffers. Requirements to exploit: A consumer must use the one-shot AIO interfaces with KCAPIINITAIO so the real AIO backend is active, hit an error after one or more IOCBs have been submitted or completed, and then free or reuse the referenced outiov buffers before all kernel completions finish. Component affected: libkcapi-1.5.0-3.el10, lib/kcapi-kernel-if.c, kcapiaioreadall(), kcapiaioreadiov(), kcapiciphercryptaio() in the one-shot AIO path Version affected: libkcapi-1.5.0-3.el10 when the handle is initialized with KCAPIINITAIO and libkcapi enables its real kernel AIO backend Patch available: no released package fix established; proposed patch included below Version fixed: unknown Upstream coordination: Unknown. CVSS: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H - 6.8 (MEDIUM) AV:L - exploitation is local to the process using libkcapi. AC:L - once the real AIO path is active, the unsafe behavior is reached directly through documented error paths after request submission. PR:N - no elevated privileges are required beyond the ability to exercise the affected API in the local process. UI:N - no separate user interaction is required. S:U - the impact stays within the security scope of the calling process. C:L - late writes into reused buffers can expose limited process data. I:L - late kernel writes can alter caller memory after the library has reported failure. A:H - heap corruption or process termination is a realistic outcome. Impact: Moderate. This flaw can cause real process memory corruption, but it depends on an opt-in AIO configuration, kernel AIO availability, and an error path after submission rather than a default or easily reachable execution path. Under Red Hat's severity guidance, that is more consistent with Moderate impact than Important or Critical. Embargo: no Reason: the issue is local and configuration-dependent, requires explicit AIO use plus an error-path trigger, and does not present a straightforward remote compromise scenario. Acknowledgement: Aisle Research Vulnerability Details: In the affected one-shot AIO path, libkcapi can return failure before all submitted kernel requests are drained. kcapiaioreadall() returns immediately on the first negative completion result, and kcapiaioreadiov() returns immediately on a short iosubmit() result even if some IOCBs were already submitted. kcapiciphercryptaio() then propagates that error directly to the caller. If the caller treats the operation as failed and promptly frees or reuses outiov[].iovbase, later kernel completions may still write into those buffers. c if (events[i].res < 0) { handle->aio.iocbret[events[i].data] = events[i].res; return (int)events[i].res; } ... ret = iosubmit(handle->aio.aioctx, (long)iovlen, handle->aio.ciopp); if ((uint32t)ret != iovlen) { if (ret < 0) { ret = -errno; kcapidolog(KCAPILOGERR, "ioread Error: %d\n", ret); return ret; } else { kcapidolog(KCAPILOGERR, "Could not sumbit AIO read\n"); return -EIO; } } c ret = kcapiaioreadiov(handle, outiov, process); if (ret < 0) return ret; The issue is not established for the default synchronous path. Reachability depends on the caller enabling KCAPIINITAIO so libkcapi uses the real kernel AIO backend. Steps to reproduce: 1. Build an ASAN-enabled harness that calls kcapicipherencryptaio() or kcapiaeaddecryptaio() with multiple output iovec entries. 2. Initialize the handle with KCAPIINITAIO so the real AIO path is active. 3. Force a deterministic short-submit path with an LDPRELOAD wrapper around syscall(NRiosubmit, ...) that returns 0 < ret < iovlen after forwarding only the first N IOCBs. 4. Optionally fault-inject iogetevents() so one returned event has res < 0 before all completions are consumed. 5. When the API returns an error, immediately free or reallocate the outiov[].iovbase buffers. 6. Observe delayed writes into freed or reused memory, for example as an ASAN use-after-free, heap corruption, or a canary mismatch. Mitigation: Until a fix is available, avoid initializing affected handles with KCAPIINITAIO and prefer the synchronous interfaces. If the real AIO path must remain enabled, applications should not immediately free or reuse outiov buffers after an error return. Proposed Fix: Drain all submitted requests before returning an error. A minimal approach is to record the first completion error, continue draining outstanding completions, and drain any successfully submitted subset after a short iosubmit() result. diff diff --git a/lib/kcapi-kernel-if.c b/lib/kcapi-kernel-if.c — a/lib/kcapi-kernel-if.c +++ b/lib/kcapi-kernel-if.c @@ -420,6 +420,7 @@ int kcapiaioreadall(struct kcapihandle handle, sizet toread, struct timespec timeout) { + int firsterr = 0; if (toread > KCAPIAIOCONCURRENT) return -EINVAL; @@ -440,8 +441,10 @@ int kcapiaioreadall(struct kcapihandle handle, sizet toread, if (events[i].res < 0) { handle->aio.iocbret[events[i].data] = events[i].res; - return (int)events[i].res; + if (!firsterr) + firsterr = (int)events[i].res; + continue; } @@ -467,7 +470,7 @@ int kcapiaioreadall(struct kcapihandle handle, sizet toread, toread -= (uint32t)rc; } - return 0; + return firsterr; } @@ -534,15 +537,20 @@ int kcapiaioreadiov(struct kcapihandle handle, ret = iosubmit(handle->aio.aioctx, (long)iovlen, handle->aio.ciopp); if ((uint32t)ret != iovlen) { + sizet submitted = (ret > 0) ? (sizet)ret : 0; + int submiterr = (ret < 0) ? -errno : -EIO; if (ret < 0) { - ret = -errno; kcapidolog(KCAPILOGERR, "ioread Error: %d\n", ret); - return ret; } else { kcapidolog(KCAPILOGERR, "Could not sumbit AIO read\n"); - return -EIO; } + if (submitted) { + int drain = kcapiaioreadall(handle, submitted, NULL); + if (submiterr == 0 && drain < 0) + submiterr = drain; + } + return submiterr; } (Equivalent fix using iocancel + confirmed drain is also acceptable.) ------ This report was generated using AI technology. Always review AI-generated content prior to use

A flaw was found in libkcapi. When performing one-shot symmetric cipher operations on large inputs (over 64 KiB) in stateful modes such as Counter (CTR) or Cipher Block Chaining (CBC), the library improperly reuses the Initialization Vector (IV) for each internal data chunk. A remote attacker could potentially exploit this by making an application that uses libkcapi process specially crafted large inputs. This can lead to a significant weakening of data confidentiality, as the repeated IV use can expose relationships in encrypted plaintext, and may also affect data integrity by causing incorrect cryptographic processing.

A flaw was found in gnutls. Servers configured with RSA-PSK (Rivest–Shamir–Adleman – Pre-Shared Key) wrongfully matched usernames containing a NUL character with truncated usernames. A remote attacker could exploit this by sending a specially crafted username, leading to an authentication bypass. This vulnerability allows an attacker to gain unauthorized access by circumventing the authentication process.

A flaw was found in gnutls. A remote attacker could exploit an issue in the Datagram Transport Layer Security (DTLS) packet reordering logic. The comparator function, responsible for ordering DTLS packets by sequence numbers, did not correctly handle packets with duplicate sequence numbers. This could lead to unstable packet ordering or undefined behavior, resulting in a denial of service.

A flaw was found in libsolv. This heap buffer overflow occurs during the decompression of attacker-controlled compressed data within .solv files due to insufficient input validation. An attacker can provide a specially crafted .solv file, which, when processed by a vulnerable application, can lead to out-of-bounds memory access. This could result in information disclosure, alteration of program execution, or a denial of service.

A flaw was found in gnutls. This vulnerability occurs because gnutls performs case-sensitive comparisons of nameConstraints labels, specifically for dNSName (DNS) or rfc822Name (email) constraints within excludedSubtrees or permittedSubtrees. A remote attacker can exploit this by crafting a leaf certificate with casing differences in the Subject Alternative Name (SAN), leading to a policy bypass where a certificate that should be rejected is instead accepted. This could result in unauthorized access or information disclosure.

A flaw was found in libssh channel handling. In sshpacketchannelopen() in src/messages.c and sshpacketchannelopenconf() in src/channels.c, the implementation accepts a peer-controlled maximum packet size of 0 in channel open messages. That zero value is stored in channel state and later reaches channelwritecommon(), where forward progress depends on the remote maximum packet size being positive; with 0, the remaining length is never reduced and the write path loops indefinitely, consuming CPU and causing denial of service. A remote authenticated peer can trigger this by advertising a zero maximum packet size in SSHMSGCHANNELOPEN or SSHMSGCHANNELOPENCONFIRMATION.

A flaw was found in libssh client-side ProxyCommand handling. In sshsocketconnectproxycommand() in src/socket.c, the return value of fork() was not checked before being stored as the proxy child PID. If fork() fails, the value -1 can be retained in state and later used during cleanup, causing signals to be sent across the caller's accessible process tree. In deployments that use ProxyCommand, this can lead to local denial of service.

A flaw was found in libssh server-side SFTP request handling. In sftpmakeclientmessage() and the downstream processread() path in src/sftpserver.c, the implementation accepts a client-controlled SSHFXPREAD length without enforcing a reasonable upper bound. The parsed len field later drives memory allocation in the SFTP server read path, so a remote authenticated client can request an excessively large read length and force the server to allocate excessive memory. Repeated requests can exhaust available memory and lead to denial of service.

A flaw was found in libssh username handling for ProxyCommand expansion. The sshcheckusernamesyntax() validation path in src/misc.c used an incomplete dangerous-character filter for usernames expanded through %r. As a result, specially crafted usernames containing shell-significant characters could reach shell-evaluated ProxyCommand handling and influence shell expansion, exposing environment variables and causing unintended shell behavior. This issue affects clients that combine untrusted username input with ProxyCommand-style shell execution.

A flaw was found in libssh builds using the OpenSSL backend for AES-GCM. In the decrypt path in src/libcrypto.c, the return value from EVPDecryptFinal() was checked incorrectly, so authentication tag verification failures were not handled as integrity failures. This could effectively remove integrity protection for affected AES-GCM sessions and allow an in-path attacker to modify plaintext on the wire without detection.

A flaw was found in libssh client-side SFTP message handling. In sftpgetmessage() in src/sftpcommon.c, SFTP responses carrying unknown request IDs were accepted and kept queued instead of being rejected. A malicious SFTP server can repeatedly send responses for request IDs that were never issued by the client, causing unbounded growth of queued messages and leading to client-side memory exhaustion and denial of service.

A flaw was found in libssh channel data handling. In channelrcvdata() in src/channels.c, incoming channel DATA messages could still be processed after the channel had already been marked as remotely closed. In SFTP-backed applications and other callback-driven consumers, this creates a path where data callbacks may observe channel-associated state after it has already been torn down or freed, leading to crashes and possible use-after-free conditions.

NGINX ngxhttpproxyv2module and ngxhttpgrpcmodule vulnerability

A flaw was found in libarchive. This heap out-of-bounds read vulnerability exists in the RAR archive processing logic due to improper validation of the LZSS sliding window size after transitions between compression methods. A remote attacker can exploit this by providing a specially crafted RAR archive, leading to the disclosure of sensitive heap memory information without requiring authentication or user interaction.

A flaw was found in binutils. A heap-buffer-overflow vulnerability exists when processing a specially crafted XCOFF (Extended Common Object File Format) object file during linking. A local attacker could trick a user into processing this malicious file, which could lead to arbitrary code execution, allowing the attacker to run unauthorized commands, or cause a denial of service, making the system unavailable.

This is a vulnerability report sent to us through https://issues.redhat.com/browse/PSIRTSUPT-17918 and was created using the PoC auto-triage agents. It contains hints on the vulnerability extracted by the IA and the full report. ALWAYS review it before any action. Once working on this, don't forget to also update the JSM ticket.

Multiple Use-After-Free vulnerabilities were found in the addarchiveelement function in ld/ldmain.c of the GNU linker (ld), a component of binutils. The root cause is that pluginmaybeclaim() in ld/plugin.c frees the original BFD object via bfdclose/bfddeletebfd when entry->thebfd->myarchive == NULL, but the caller retains both the original abfd parameter and a shallow copy (originput.thebfd) as dangling pointers. These dangling pointers are subsequently dereferenced at three distinct locations in addarchiveelement:

1. Line ~1442: accessing abfd->myarchive via bfdusrdata(abfd->myarchive) 2. Line ~1493: multiple accesses to abfd and abfd->myarchive in a conditional check and bfdgetfilename call 3. Line ~1525: dereferencing the shallow copy originput.thebfd->myarchive in trace/verbose logging

The vulnerability is triggered when LTO plugins are active (linkinfo.ltopluginactive is true) and the input object has abfd->myarchive == NULL, which is a valid state for standalone object files. Red Hat builds binutils with --enable-plugins and --enable-lto, confirming the vulnerable code path is compiled in and reachable.

An attacker who can supply a crafted object or archive file to a build process using LTO-enabled linking could exploit this flaw to cause a denial of service (linker crash via segmentation fault). Arbitrary code execution is theoretically possible through heap manipulation but is substantially mitigated by hardening measures including stack protector, FORTIFYSOURCE, ASLR, and PIE.

The attack surface is limited to build-time environments — the linker is a development tool not exposed in production runtime. The most realistic exploitation scenario is a supply chain attack introducing a crafted object file as a build dependency in CI/CD pipelines or development environments.

A flaw was found in OpenSSH. A malicious SSH server can exploit a double free vulnerability in the Diffie-Hellman Group Exchange (DH-GEX) client path. This occurs during FIPS (Federal Information Processing Standards) mode known-group validation when the client processes attacker-controlled DH-GEX group parameters. Successful exploitation leads to client-side process termination, resulting in a Denial of Service (DoS).

A flaw was found in binutils, specifically within the readelf utility. This vulnerability allows a local attacker to cause a Denial of Service (DoS) by tricking a user into processing a specially crafted Executable and Linkable Format (ELF) file. The exploitation of this flaw can lead to the system becoming unresponsive due to excessive resource consumption or a program crash.

A flaw was identified in the RelaxNG parser of libxml2 related to how external schema inclusions are handled. The parser does not enforce a limit on inclusion depth when resolving nested <include> directives. Specially crafted or overly complex schemas can cause excessive recursion during parsing. This may lead to stack exhaustion and application crashes, creating a denial-of-service risk.

A flaw was found in p11-kit. A remote attacker could exploit this vulnerability by calling the CDeriveKey function on a remote token with specific IBM kyber or IBM btc derive mechanism parameters set to NULL. This could lead to the RPC-client attempting to return an uninitialized value, potentially resulting in a NULL dereference or undefined behavior. This issue may cause an application level denial of service or other unpredictable system states.

A flaw was found in libarchive. An Undefined Behavior vulnerability exists in the zisofs decompression logic, caused by improper validation of a field (pzlog2bs) read from ISO9660 Rock Ridge extensions. A remote attacker can exploit this by supplying a specially crafted ISO file. This can lead to incorrect memory allocation and potential application crashes, resulting in a denial-of-service (DoS) condition.

A flaw was found in gnutls. A remote attacker could exploit this vulnerability by presenting a specially crafted Online Certificate Status Protocol (OCSP) response during a TLS handshake. Due to a logic error in how gnutls processes multi-record OCSP responses, a client with OCSP verification enabled may incorrectly accept a revoked server certificate, potentially leading to a compromise of trust.

A flaw was found in gnutls. A remote, unauthenticated attacker can exploit this vulnerability by sending a specially crafted ClientHello message with an invalid Pre-Shared Key (PSK) binder value during the TLS handshake. This can lead to a NULL pointer dereference, causing the server to crash and resulting in a remote Denial of Service (DoS) condition.