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).

Accounts. The issue was addressed with improved checks.

glibc is vulnerable to a denial of service, caused by a memory allocation failure when the Name Service Cache Daemon's (nscd) netgroup cache uses the xmalloc or xrealloc functions. A local attacker could exploit this vulnerability to terminate the daemon.

A double-free vulnerability was found in OpenSSL's PEMreadbioex function. The function PEMreadbioex() reads a PEM file from a BIO and parses and decodes the "name" (for example, "CERTIFICATE"), any header data, and the payload data. If the function succeeds, then the "nameout," "header," and "data" arguments are populated with pointers to buffers containing the relevant decoded data. The caller is responsible for freeing those buffers. Constructing a PEM file that results in 0 bytes of payload data is possible. In this case, PEMreadbioex() will return a failure code but will populate the header argument with a pointer to a freed buffer. A double-free will occur if the caller also frees this buffer. This will most likely lead to a crash. This could be exploited by an attacker who can supply malicious PEM files for parsing to achieve a denial of service attack.

A flaw was found in Apache Commons FileUpload, where it does not limit the number of parts being processed in a request. This issue may allow an attacker to use a malicious upload or series of uploads to trigger a denial of service. While Red Hat Satellite relies upon Apache Tomcat, it does not directly ship it. Tomcat is shipped with Red Hat Enterprise Linux and consumed by the Candlepin component of Satellite. Red Hat Satellite users are therefore advised to check the impact state of Red Hat Enterprise Linux, since any necessary fixes will be distributed through the platform.

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.

Last updated 24 September 2025

An issue was discovered in Python before 3.8.18, 3.9.x before 3.9.18, 3.10.x before 3.10.13, and 3.11.x before 3.11.5. It primarily affects servers (such as HTTP servers) that use TLS client authentication. If a TLS server-side socket is created, receives data into the socket buffer, and then is closed quickly, there is a brief window where the SSLSocket instance will detect the socket as "not connected" and won't initiate a handshake, but buffered data will still be readable from the socket buffer. This data will not be authenticated if the server-side TLS peer is expecting client certificate authentication, and is indistinguishable from valid TLS stream data. Data is limited in size to the amount that will fit in the buffer. (The TLS connection cannot directly be used for data exfiltration because the vulnerable code path requires that the connection be closed on initialization of the SSLSocket.)

A flaw in the Linux Kernel found. A use-after-free vulnerability in the Linux kernel's net/sched: clsfw component can be exploited to achieve local privilege escalation. If tcfchangeindev() fails, fwsetparms() will immediately return an error after incrementing or decrementing the reference counter in tcfbindfilter(). If an attacker can control the reference counter and set it to zero, they can cause the reference to be freed, leading to a use-after-free vulnerability.

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit?id=0323bce598eea038714f941ce2b22541c46d488f

A flaw in the Linux Kernel found. An out-of-bounds write vulnerability in the Linux kernel's net/sched: schqfq component can be exploited to achieve local privilege escalation. The qfqchangeagg() function in net/sched/schqfq.c allows an out-of-bounds write because lmax is updated according to packet sizes without bounds checks.

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=3e337087c3b5805fe0b8a46ba622a962880b5d64

Diffie-Hellman key agreement protocol is vulnerable to a denial of service, caused by the use of long exponents that arguably make certain calculations unnecessarily expensive. By sending specially-crafted network traffic, a remote attacker could exploit this vulnerability to cause a denial of service.

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.

ext/fts3/fts3.c in SQLite before 3.32.0 has a use-after-free in fts3EvalNextRow related to the snippet feature.

Accounts. A logic issue was addressed with improved file handling.

Apache HTTP Server is vulnerable to server-side request forgery, caused by a flaw in the modrewrite. By sending a specially crafted request, an attacker could exploit this vulnerability to cause unsafe RewriteRules to unexpectedly setup URL's to be handled by modproxy.