A use after free can have a range of potential consequences such as the corruption of valid data, crashes or execution of arbitrary code. However, only applications that directly call the SSLfreebuffers function are affected by this issue. Applications that do not call this function are not vulnerable. Our investigations indicate that this function is rarely used by applications.

The SSLfreebuffers function is used to free the internal OpenSSL buffer used when processing an incoming record from the network. The call is only expected to succeed if the buffer is not currently in use. However, two scenarios have been identified where the buffer is freed even when still in use.

The first scenario occurs where a record header has been received from the network and processed by OpenSSL, but the full record body has not yet arrived. In this case calling SSLfreebuffers will succeed even though a record has only been partially processed and the buffer is still in use.

The second scenario occurs where a full record containing application data has been received and processed by OpenSSL but the application has only read part of this data. Again a call to SSLfreebuffers will succeed even though the buffer is still in use.

While these scenarios could occur accidentally during normal operation a malicious attacker could attempt to engineer a stituation where this occurs. We are not aware of this issue being actively exploited.

The FIPS modules in 3.3, 3.2, 3.1 and 3.0 are not affected by this issue.

OpenSSL 1.0.2 is also not affected by this issue.

OpenSSL 3.3, 3.2, 3.1, 3.0 and 1.1.1 are vulnerable to this issue.

OpenSSL 3.3 users should upgrade to OpenSSL 3.3.1 once it is released.

OpenSSL 3.2 users should upgrade to OpenSSL 3.2.2 once it is released.

OpenSSL 3.1 users should upgrade to OpenSSL 3.1.6 once it is released.

OpenSSL 3.0 users should upgrade to OpenSSL 3.0.14 once it is released.

OpenSSL 1.1.1 users should upgrade to OpenSSL 1.1.1y once it is released (premium support customers only).

Due to the low severity of this issue we are not issuing new releases of OpenSSL at this time. The fix will be included in the next releases when they become available. The fix is also available in commit e5093133c3 (for 3.3), commit c88c3de510 (for 3.2), commit 704f725b96 (for 3.1) and commit b3f0eb0a29 (for 3.0) in the OpenSSL git repository. It is available to premium support customers in commit f7a045f314 (for 1.1.1).

This issue was reported on 10th April 2024 by William Ahern (Akamai). The fix was developed by Matt Caswell and Watson Ladd (Akamai).

Excessive time spent checking DSA keys and parameters

Issue summary: Use of the low-level GF(2^m) elliptic curve APIs with untrusted explicit values for the field polynomial can lead to out-of-bounds memory reads or writes.

Impact summary: Out of bound memory writes can lead to an application crash or even a possibility of a remote code execution, however, in all the protocols involving Elliptic Curve Cryptography that we're aware of, either only "named curves" are supported, or, if explicit curve parameters are supported, they specify an X9.62 encoding of binary (GF(2^m)) curves that can't represent problematic input values. Thus the likelihood of existence of a vulnerable application is low.

In particular, the X9.62 encoding is used for ECC keys in X.509 certificates, so problematic inputs cannot occur in the context of processing X.509 certificates. Any problematic use-cases would have to be using an "exotic" curve encoding.

The affected APIs include: ECGROUPnewcurveGF2m(), ECGROUPnewfromparams(), and various supporting BNGF2m() functions.

Applications working with "exotic" explicit binary (GF(2^m)) curve parameters, that make it possible to represent invalid field polynomials with a zero constant term, via the above or similar APIs, may terminate abruptly as a result of reading or writing outside of array bounds. Remote code execution cannot easily be ruled out.

The FIPS modules in 3.3, 3.2, 3.1 and 3.0 are not affected by this issue.

Abnormal termination of an application can a cause a denial of service.

Applications performing certificate name checks (e.g., TLS clients checking server certificates) may attempt to read an invalid memory address when comparing the expected name with an otherName subject alternative name of an X.509 certificate. This may result in an exception that terminates the application program.

Note that basic certificate chain validation (signatures, dates, ...) is not affected, the denial of service can occur only when the application also specifies an expected DNS name, Email address or IP address.

TLS servers rarely solicit client certificates, and even when they do, they generally don't perform a name check against a "reference identifier" (expected identity), but rather extract the presented identity after checking the certificate chain. So TLS servers are generally not affected and the severity of the issue is Moderate.

The FIPS modules in 3.3, 3.2, 3.1 and 3.0 are not affected by this issue. OpenSSL 1.1.1 and 1.0.2 are also not affected by this issue.

OpenSSL 3.3, 3.2, 3.1 and 3.0 are vulnerable to this issue.

OpenSSL 3.3 users should upgrade to OpenSSL 3.3.2

OpenSSL 3.2 users should upgrade to OpenSSL 3.2.3

OpenSSL 3.1 users should upgrade to OpenSSL 3.1.7

OpenSSL 3.0 users should upgrade to OpenSSL 3.0.15

A flaw has been identified in glibc. In an uncommon situation, the gaihinet function may use memory that has been freed, resulting in an application crash. This issue is only exploitable when the getaddrinfo function is called and the hosts database in /etc/nsswitch.conf is configured with SUCCESS=continue or SUCCESS=merge.

Issue summary: Some non-default TLS server configurations can cause unbounded memory growth when processing TLSv1.3 sessions

A flaw was found in glibc. When the getaddrinfo function is called with the AFUNSPEC address family and the system is configured with no-aaaa mode via /etc/resolv.conf, a DNS response via TCP larger than 2048 bytes can potentially disclose stack contents through the function returned address data, and may cause a crash.

A buffer overflow was discovered in the GNU C Library's dynamic loader ld.so while processing the GLIBCTUNABLES environment variable. This issue could allow a local attacker to use maliciously crafted GLIBCTUNABLES environment variables when launching binaries with SUID permission to execute code with elevated privileges.

Issue summary: Clients using RFC7250 Raw Public Keys (RPKs) to authenticate a server may fail to notice that the server was not authenticated, because handshakes don't abort as expected when the SSLVERIFYPEER verification mode is set.

Impact summary: TLS and DTLS connections using raw public keys may be vulnerable to man-in-middle attacks when server authentication failure is not detected by clients.

RPKs are disabled by default in both TLS clients and TLS servers. The issue only arises when TLS clients explicitly enable RPK use by the server, and the server, likewise, enables sending of an RPK instead of an X.509 certificate chain. The affected clients are those that then rely on the handshake to fail when the server's RPK fails to match one of the expected public keys, by setting the verification mode to SSLVERIFYPEER.

Clients that enable server-side raw public keys can still find out that raw public key verification failed by calling SSLgetverifyresult(), and those that do, and take appropriate action, are not affected. This issue was introduced in the initial implementation of RPK support in OpenSSL 3.2.

The FIPS modules in 3.4, 3.3, 3.2, 3.1 and 3.0 are not affected by this issue.

A use-after-free exists in drivers/tee/teeshm.c in the TEE subsystem in the Linux kernel through 5.15.11. This occurs because of a race condition in teeshmgetfromid during an attempt to free a shared memory object.

A vulnerability was found in cgroupreleaseagentwrite in kernel/cgroup/cgroup-v1.c in the Linux kernel. In this flaw, under certain circumstances, the cgroups v1 releaseagent feature can be used to escalate privilege and bypass namespace isolation unexpectedly.

Upstream Commit:

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=24f6008564183aa120d07c03d9289519c2fe02af

A flaw was found in unrestricted eBPF usage by the BPFBTFLOAD, leading to a possible out-of-bounds memory write in the Linux kernel’s BPF subsystem due to the way a user loads BTF. This flaw allows a local user to crash or escalate their privileges on the system.

Last updated 25 April 2025

A flaw in the Linux Kernel found. If unprivileged users can mount FUSE filesystems, then can trigger use after free (UAF) that reads of write() buffers, allowing theft of (partial) /etc/shadow hashes or any other data from filesystem.

FUSE allows the userspace filesystem to specify on FUSEOPEN whether the file should use the normal kernel pagecache for handling read()/write() or just send FUSEREAD/FUSEWRITE requests directly to the userspace filesystem (using the flag FOPENDIRECTIO in fuseopenout::openflags).

In FOPENDIRECTIO mode, fusefilewriteiter() calls fusedirectwriteiter(), which normally calls fusedirectio(), which then imports the write buffer with fusegetuserpages(), which uses iovitergetpages() to grab references to userspace pages instead of actually copying memory.

On the filesystem device side, these pages can then either be read to userspace (via fusedevread()), or splice()d over into a pipe using fusedevspliceread() as pipe buffers with &nostealpipebufops.

This is wrong because after fusedevdoread() unlocks the FUSE request, the userspace filesystem can mark the request as completed, causing write() to return. At that point, the write buffer may be reused for other purposes, and the userspace filesystem should no longer have access to it.

In kernel/bpf/verifier.c , there is a possible way to manipulate pointer arithmetic due to a logic error in the code. This could lead to local escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation.

In the Linux kernel through 5.15.2, hwatlutilsfwrpcwait in drivers/net/ethernet/aquantia/atlantic/hwatl/hwatlutils.c allows an attacker (who can introduce a crafted device) to trigger an out-of-bounds write via a crafted length value.

drivers/usb/gadget/legacy/inode.c in the Linux kernel through 5.16.8 mishandles dev->buf release.

An issue was discovered in drivers/usb/gadget/composite.c in the Linux kernel before 5.16.10. The USB Gadget subsystem lacks certain validation of interface OS descriptor requests (ones with a large array index and ones associated with NULL function pointer retrieval). Memory corruption might occur.

An out-of-bounds (OOB) memory read flaw was found in the Qualcomm IPC router protocol in the Linux kernel. A missing sanity check allows a local attacker to gain access to out-of-bounds memory, leading to a system crash or a leak of internal kernel information. The highest threat from this vulnerability is to system availability.

A race problem was seen in the vtkioctl in drivers/tty/vt/vtioctl.c in the Linux kernel, which may cause an out of bounds read in vt as the write access to vcmode is not protected by lock-in vtioctl (KDSETMDE). The highest threat from this vulnerability is to data confidentiality.

In static initializers of iouring.c, there is an insecure default value. This could lead to local escalation of privilege in the kernel with no additional execution privileges needed. User interaction is not needed for exploitation.

An issue was discovered in the Linux kernel before 5.7.3, related to mm/gup.c and mm/hugememory.c. The getuserpages (aka gup) implementation, when used for a copy-on-write page, does not properly consider the semantics of read operations and therefore can grant unintended write access, aka CID-17839856fd58.

A read-after-free memory flaw was found in the Linux kernel's garbage collection for Unix domain socket file handlers in the way users call close() and fget() simultaneously and can potentially trigger a race condition. This flaw allows a local user to crash the system or escalate their privileges on the system.

An out-of-bounds (OOB) memory write flaw was found in preallocelemsandfreelist in kernel/bpf/stackmap.c in the bpf iin the Linux kernel. In this flaw, the multiplication to calculate the size could lead to an integer overflow, and this could allow a local attacker, with a special user privilege to gain access to out-of-bounds memory leading to a system crash or a leak of internal kernel information.

Reference and upstream patch: https://github.com/torvalds/linux/commit/30e29a9a2bc6a4888335a6ede968b75cd329657a

A heap buffer overflow flaw was found in IPsec ESP transformation code in net/ipv4/esp4.c and net/ipv6/esp6.c. This flaw allows a local attacker with a normal user privilege to overwrite kernel heap objects and may cause a local privilege escalation threat.

A use-after-free flaw was found in u32change in net/sched/clsu32.c in the network subcomponent of the Linux kernel. This flaw could allow a local attacker to crash the system and cause a privilege escalation, and a kernel information leak problem.

References and upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=3db09e762dc79584a69c10d74a6b98f89a9979f8 https://kernel.dance/#3db09e762dc79584a69c10d74a6b98f89a9979f8

A flaw was found in the Linux kernel. The PTRACESEIZE code path allows attackers to bypass intended restrictions on setting the PTSUSPENDSECCOMP flag, possibly disabling seccomp.

A use-after-free flaw was found in the Linux kernel’s iouring subsystem in the way a user sets up a ring with IORINGSETUPIOPOLL with more than one task completing submissions on this ring. This flaw allows a local user to crash or escalate their privileges on the system.

A use-after-free flaw was found in the Expat package, caused by destruction of a shared DTD in XMLExternalEntityParserCreate in out-of-memory situations. This may lead to availability disruptions.

A locking inconsistency issue was discovered in the tty subsystem of the Linux kernel through 5.9.13. drivers/tty/ttyio.c and drivers/tty/ttyjobctrl.c may allow a read-after-free attack against TIOCGSID, aka CID-c8bcd9c5be24.