CVE-2024-4741

What it actually does

Calling SSL_free_buffers on a partially processed TLS record frees internal buffers that remain in use, resulting in a use-after-free condition that can corrupt memory, cause denial of service, or enable arbitrary code execution.

Why it matters to the business

Applications that directly invoke the rarely-used SSL_free_buffers function face elevated risk of crashes or remote code execution; most deployments are unaffected but must still verify they do not call the function and apply the patch to eliminate residual exposure.

How an attack unfolds

An attacker sends a TLS record header without the full body or sends a full record but reads only part of the application data, then triggers an application call to SSL_free_buffers while the buffer is still referenced, leading to use-after-free.

How to fix it

Upgrade OpenSSL to the commit 704f725b96aa373ee45ecfb23f6abfe8be8d9177 or later; applications should avoid direct calls to SSL_free_buffers and review any custom TLS buffer-management code.

How to confirm the fix worked

Confirm the installed OpenSSL version or commit contains 704f725b96aa373ee45ecfb23f6abfe8be8d9177; audit source for direct calls to SSL_free_buffers and test with partial-record TLS traffic.

Typical attack path

1. Establish a TLS connection to the target
2. Send a partial TLS record header or a full record followed by partial application-data reads
3. Induce the application to invoke SSL_free_buffers on the connection
4. Trigger reuse of the now-freed buffer to achieve memory corruption or code execution

How to detect it

Review application source and logs for direct calls to SSL_free_buffers; inspect TLS traffic logs for partial record patterns followed by crashes or unexpected memory behavior; no public exploitation artifacts are known.

What your security team should do

• Immediately inventory all OpenSSL deployments and identify any code paths that call SSL_free_buffers
• Apply the fixed commit 704f725b96aa373ee45ecfb23f6abfe8be8d9177 to all affected instances
• Add static-analysis rules to block future direct use of SSL_free_buffers
• Monitor vendor advisories for downstream packages that embed the vulnerable OpenSSL version