OpenSSL Security Advisory: CVE-2024-4741 Use After Free in SSL_free_buffers

OpenSSL Security Advisory [28th May 2024] Use After Free with SSL_free_buffers (CVE-2024-4741) --- Severity: Low Issue summary: Calling the OpenSSL API function may cause memory to be accessed that was previously freed in some situations. Impact summary: A use-after-free vulnerability can lead to various consequences, such as data corruption, crashes, or execution of arbitrary code. However, only applications that directly call the 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 function is used to free the internal OpenSSL buffer used when processing an incoming record from the network. The call is expected to succeed only 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 when 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 will succeed even though the record has only been partially processed and the buffer is still in use. The second scenario occurs when 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 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 such a situation. We are not aware of this issue being actively exploited. The FIPS modules in OpenSSL 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 (for 3.3), commit (for 3.2), commit (for 3.1), and commit (for 3.0) in the OpenSSL git repository. It is available to premium support customers in commit (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). --- General Advisory Notes URL for this Security Advisory: https://www.openssl.org/news/secadv/20240528.txt Note: The online version of the advisory may be updated with additional details over time. For details of OpenSSL severity classifications please see: https://www.openssl.org/policies/secpolicy.html

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OpenSSL Security Advisory: CVE-2024-4741 Use After Free in SSL_free_buffers