A vulnerability has been found in GNU Binutils 2.45. The affected element is the function elfswapshdr in the library bfd/elfcode.h of the component Linker. The manipulation leads to heap-based buffer overflow. The attack must be carried out locally. The exploit has been disclosed to the public and may be used. The identifier of the patch is 9ca499644a21ceb3f946d1c179c38a83be084490. To fix this issue, it is recommended to deploy a patch. The code maintainer replied with "[f]ixed for 2.46".

A use-after-free vulnerability was found in libxslt while parsing xsl nodes that may lead to the dereference of expired pointers and application crash.

Accessibility. A privacy issue was addressed by removing sensitive data.

In the Linux kernel, the following vulnerability has been resolved:

mm: fix zswap writeback race condition

The zswap writeback mechanism can cause a race condition resulting in memory corruption, where a swapped out page gets swapped in with data that was written to a different page.

The race unfolds like this: 1. a page with data A and swap offset X is stored in zswap 2. page A is removed off the LRU by zpool driver for writeback in zswap-shrink work, data for A is mapped by zpool driver 3. user space program faults and invalidates page entry A, offset X is considered free 4. kswapd stores page B at offset X in zswap (zswap could also be full, if so, page B would then be IOed to X, then skip step 5.) 5. entry A is replaced by B in tree->rbroot, this doesn't affect the local reference held by zswap-shrink work 6. zswap-shrink work writes back A at X, and frees zswap entry A 7. swapin of slot X brings A in memory instead of B

The fix: Once the swap page cache has been allocated (case ZSWAPSWAPCACHENEW), zswap-shrink work just checks that the local zswapentry reference is still the same as the one in the tree. If it's not the same it means that it's either been invalidated or replaced, in both cases the writeback is aborted because the local entry contains stale data.

Reproducer: I originally found this by running stress overnight to validate my work on the zswap writeback mechanism, it manifested after hours on my test machine. The key to make it happen is having zswap writebacks, so whatever setup pumps /sys/kernel/debug/zswap/writtenbackpages should do the trick.

In order to reproduce this faster on a vm, I setup a system with ~100M of available memory and a 500M swap file, then running stress --vm 1 --vm-bytes 300000000 --vm-stride 4000 makes it happen in matter of tens of minutes. One can speed things up even more by swinging /sys/module/zswap/parameters/maxpoolpercent up and down between, say, 20 and 1; this makes it reproduce in tens of seconds. It's crucial to set --vm-stride to something other than 4096 otherwise stress won't realize that memory has been corrupted because all pages would have the same data.

A flaw has been found in GNU Binutils 2.45. Impacted is the function bfdelfparseehframe of the file bfd/elf-eh-frame.c of the component Linker. Executing manipulation can lead to heap-based buffer overflow. The attack is restricted to local execution. The exploit has been published and may be used. This patch is called ea1a0737c7692737a644af0486b71e4a392cbca8. A patch should be applied to remediate this issue. The code maintainer replied with "[f]ixed for 2.46".

802.1X. An authentication issue was addressed with improved state management.

In libxml2 before 2.10.4, parsing of certain invalid XSD schemas can lead to a NULL pointer dereference and subsequently a segfault. This occurs in xmlSchemaFixupComplexType in xmlschemas.c.

Accounts. The issue was addressed with improved checks.

Dear Linux Developers,

We're reaching out to you as part of the disclosure process of our research.

In our research, which we will present at IEEE Security & Privacy in May 2024, we found that attackers can not only create TCP-spoofed connections (which was already known), but can also reliably transmit IP-spoofed data over such connections. This has security implications for applications that rely on TCP endpoint IP addresses, such as firewalling or host-based authentication (e.g., SMTP/SPF, of DBs).

We basically discovered two TCP spoofing primitives. First, attackers can bruteforce the server-chosen send window by acknowledging data that was never sent (what we call "ghost ACKs"; see Figure 3 in the paper). Second, we show that there are side channels that allow the attacker to leak the otherwise-secret server-chosen initial sequence number (ISN). One of these side channels leverages TCP SYN cookies.

We believe that the TCP/IP stack can take countermeasures to prevent such attacks, or at least make them harder. For example, we think that TCP endpoints should ignore ghost ACKs, and have some ideas to randomize the TCP backlog queue to prevent the SYN cookie side channel.

At the same time, we have disclosed our findings to the IETF folks and hope that they have helpful feedback for us.

Excessive time spent in DH check / generation with large Q parameter value

Prior to Apache HTTP Server 2.4.55, a malicious backend can cause the response headers to be truncated early, resulting in some headers being incorporated into the response body. If the later headers have any security purpose, they will not be interpreted by the client.

CPython 3.9 and earlier doesn't disallow configuring an empty list ("[]") for SSLContext.setnpnprotocols() which is an invalid value for the underlying OpenSSL API. This results in a buffer over-read when NPN is used (see CVE-2024-5535 for OpenSSL). This vulnerability is of low severity due to NPN being not widely used and specifying an empty list likely being uncommon in-practice (typically a protocol name would be configured).

A vulnerability was found in GnuTLS. The response times to malformed ciphertexts in RSA-PSK ClientKeyExchange differ from the response times of ciphertexts with correct PKCS#1 v1.5 padding. This issue may allow a remote attacker to perform a timing side-channel attack in the RSA-PSK key exchange, potentially leading to the leakage of sensitive data. CVE-2024-0553 is designated as an incomplete resolution for CVE-2023-5981.

A use-after-free flaw was found in route4change in the net/sched/clsroute.c filter implementation in the Linux kernel. This flaw allows a local user to crash the system and possibly lead to a local privilege escalation problem.

Validating the order of the public keys in the Diffie-Hellman Key Agreement Protocol, when an approved safe prime is used, allows remote attackers (from the client side) to trigger unnecessarily expensive server-side DHE modular-exponentiation calculations. The client may cause asymmetric resource consumption. The basic attack scenario is that the client must claim that it can only communicate with DHE, and the server must be configured to allow DHE and validate the order of the public key.

In libxml2 before 2.10.4, parsing of certain invalid XSD schemas can lead to a NULL pointer dereference and subsequently a segfault. This occurs in xmlSchemaFixupComplexType in xmlschemas.c.

CVE-2024-39279 Insufficient granularity of access control in UEFI firmware in some Intel(R) processors may allow a authenticated user to potentially enable denial of service via local access. CVE-2024-28047 Improper input validation in UEFI firmware for some Intel(R) Processors may allow a privileged user to potentially enable information disclosure via local access.

CVE-2024-39279 Insufficient granularity of access control in UEFI firmware in some Intel(R) processors may allow a authenticated user to potentially enable denial of service via local access. CVE-2024-28047 Improper input validation in UEFI firmware for some Intel(R) Processors may allow a privileged user to potentially enable information disclosure via local access.

CVE-2024-39279 Insufficient granularity of access control in UEFI firmware in some Intel(R) processors may allow a authenticated user to potentially enable denial of service via local access. CVE-2024-28047 Improper input validation in UEFI firmware for some Intel(R) Processors may allow a privileged user to potentially enable information disclosure via local access.

CVE-2023-5981 A vulnerability was found that the response times to malformed ciphertexts in RSA-PSK ClientKeyExchange differ from response times of ciphertexts with correct PKCS#1 v1.5 padding. CVE-2024-0553 A vulnerability was found in GnuTLS. The response times to malformed ciphertexts in RSA-PSK ClientKeyExchange differ from the response times of ciphertexts with correct PKCS#1 v1.5 padding. This issue may allow a remote attacker to perform a timing side-channel attack in the RSA-PSK key exchange, potentially leading to the leakage of sensitive data. CVE-2024-0553 is designated as an incomplete resolution for CVE-2023-5981.

A vulnerability was found that the response times to malformed ciphertexts in RSA-PSK ClientKeyExchange differ from response times of ciphertexts with correct PKCS#1 v1.5 padding.

Improper input validation in UEFI firmware for some Intel(R) Processors may allow a privileged user to enable information disclosure or denial of service via local access.

In the Linux kernel, the following vulnerability has been resolved: tcp: do not accept ACK of bytes we never sent This patch is based on a detailed report and ideas from Yepeng Pan and Christian Rossow. ACK seq validation is currently following RFC 5961 5.2 guidelines: The ACK value is considered acceptable only if it is in the range of ((SND.UNA - MAX.SND.WND) <= SEG.ACK <= SND.NXT). All incoming segments whose ACK value doesn't satisfy the above condition MUST be discarded and an ACK sent back. It needs to be noted that RFC 793 on page 72 (fifth check) says: "If the ACK is a duplicate (SEG.ACK < SND.UNA), it can be ignored. If the ACK acknowledges something not yet sent (SEG.ACK > SND.NXT) then send an ACK, drop the segment, and return". The "ignored" above implies that the processing of the incoming data segment continues, which means the ACK value is treated as acceptable. This mitigation makes the ACK check more stringent since any ACK < SND.UNA wouldn't be accepted, instead only ACKs that are in the range ((SND.UNA - MAX.SND.WND) <= SEG.ACK <= SND.NXT) get through. This can be refined for new (and possibly spoofed) flows, by not accepting ACK for bytes that were never sent. This greatly improves TCP security at a little cost. I added a Fixes: tag to make sure this patch will reach stable trees, even if the 'blamed' patch was adhering to the RFC. tp->bytesacked was added in linux-4.2 Following packetdrill test (courtesy of Yepeng Pan) shows the issue at hand: 0 socket(..., SOCKSTREAM, IPPROTOTCP) = 3 +0 setsockopt(3, SOLSOCKET, SOREUSEADDR, [1], 4) = 0 +0 bind(3, ..., ...) = 0 +0 listen(3, 1024) = 0 // ---------------- Handshake ------------------- // // when window scale is set to 14 the window size can be extended to // 65535 (2^14) = 1073725440. Linux would accept an ACK packet // with ack number in (ServerISN+1-1073725440. ServerISN+1) // ,though this ack number acknowledges some data never // sent by the server. +0 < S 0:0(0) win 65535 +0 > S. 0:0(0) ack 1 <...> +0 < . 1:1(0) ack 1 win 65535 +0 accept(3, ..., ...) = 4 // For the established connection, we send an ACK packet, // the ack packet uses ack number 1 - 1073725300 + 2^32, // where 2^32 is used to wrap around. // Note: we used 1073725300 instead of 1073725440 to avoid possible // edge cases. // 1 - 1073725300 + 2^32 = 3221241997 // Oops, old kernels happily accept this packet. +0 < . 1:1001(1000) ack 3221241997 win 65535 // After the kernel fix the following will be replaced by a challenge ACK, // and prior malicious frame would be dropped. +0 > . 1:1(0) ack 1001

Improper access control in the BIOS firmware for some Intel(R) Processors may allow a privileged user to potentially enable escalation of privilege via local access.

Improper access control in the BIOS firmware for some Intel(R) Processors may allow a privileged user to potentially enable escalation of privilege via local access.

Prior to Apache HTTP Server 2.4.55, a malicious backend can cause the response headers to be truncated early, resulting in some headers being incorporated into the response body. If the later headers have any security purpose, they will not be interpreted by the client.

Improper input validation in the UEFI WheaERST module for some Intel(R) reference platforms may allow an escalation of privilege. System software adversary with a privileged user combined with a high complexity attack may enable escalation of privilege. This result may potentially occur via local access when attack requirements are present without special internal knowledge and requires no user interaction. The potential vulnerability may impact the confidentiality (high), integrity (high) and availability (high) of the vulnerable system, resulting in subsequent system confidentiality (none), integrity (none) and availability (none) impacts.

Improper input validation in the UEFI WheaERST module for some Intel(R) reference platforms may allow an escalation of privilege. System software adversary with a privileged user combined with a high complexity attack may enable escalation of privilege. This result may potentially occur via local access when attack requirements are present without special internal knowledge and requires no user interaction. The potential vulnerability may impact the confidentiality (high), integrity (high) and availability (high) of the vulnerable system, resulting in subsequent system confidentiality (none), integrity (none) and availability (none) impacts.

Issue summary: Generating excessively long X9.42 DH keys or checking excessively long X9.42 DH keys or parameters may be very slow. Impact summary: Applications that use the functions DHgeneratekey() to generate an X9.42 DH key may experience long delays. Likewise, applications that use DHcheckpubkey(), DHcheckpubkeyex() or EVPPKEYpubliccheck() to check an X9.42 DH key or X9.42 DH parameters may experience long delays. Where the key or parameters that are being checked have been obtained from an untrusted source this may lead to a Denial of Service. While DHcheck() performs all the necessary checks (as of CVE-2023-3817), DHcheckpubkey() doesn't make any of these checks, and is therefore vulnerable for excessively large P and Q parameters. Likewise, while DHgeneratekey() performs a check for an excessively large P, it doesn't check for an excessively large Q. An application that calls DHgeneratekey() or DHcheckpubkey() and supplies a key or parameters obtained from an untrusted source could be vulnerable to a Denial of Service attack. DHgeneratekey() and DHcheckpubkey() are also called by a number of other OpenSSL functions. An application calling any of those other functions may similarly be affected. The other functions affected by this are DHcheckpubkeyex(), EVPPKEYpubliccheck(), and EVPPKEYgenerate(). Also vulnerable are the OpenSSL pkey command line application when using the "-pubcheck" option, as well as the OpenSSL genpkey command line application. The OpenSSL SSL/TLS implementation is not affected by this issue. The OpenSSL 3.0 and 3.1 FIPS providers are not affected by this issue.

A use-after-free vulnerability was found in libxslt while parsing XSL nodes that may lead to the dereference of expired pointers and application crash.