FixVibe
Covered by FixVibemedium

Unbounded Memory Growth in TLSv1.3 Session Processing (CVE-2024-2511)

CVE-2024-2511 affects specific non-default TLSv1.3 server configurations in vulnerable OpenSSL release lines, where session handling can grow memory without bound and cause denial of service. FixVibe reports this as repository source/config evidence, not confirmed live exploitability.

CVE-2024-2511CWE-1325

Attacker Impact

A server that uses an affected OpenSSL release line and the relevant non-default TLSv1.3 session configuration can experience unbounded memory growth while processing sessions [S1]. A remote client may be able to drive that condition into denial of service, although OpenSSL assessed the issue as Low severity because the vulnerable path depends on specific server-side configuration and does not affect TLS clients [S1]. NVD lists a CISA ADP CVSS 3.1 score in the Medium range, but NVD itself has not provided its own enrichment score [S2].

Root Cause

The issue is in OpenSSL TLSv1.3 session handling when a server uses the non-default no-ticket behavior described in the vendor advisory [S1]. Under those conditions, the session cache can fail to flush properly and continue growing [S1]. The OpenSSL advisory also notes important boundaries: clients are not affected, OpenSSL 1.0.2 is not affected, and the FIPS modules for the listed 3.x branches are not affected [S1].

Concrete Fixes

  • Upgrade the active OpenSSL runtime: Move the TLS-serving runtime to the fixed release for its branch: 3.2.2, 3.1.6, 3.0.14, or 1.1.1y for premium-support 1.1.1 deployments, or to a vendor-patched equivalent [S1]. Rebuild and redeploy the binary, container image, or host package that actually terminates TLS.
  • Review TLS session configuration: Confirm whether the no-ticket/session-ticket-off behavior is required. If it must remain enabled, make sure the patched OpenSSL runtime is the one handling production TLS. Document any early-data anti-replay exception rather than treating source evidence alone as proof of exposure [S1].

What FixVibe checks

FixVibe repo scans can now correlate affected OpenSSL version evidence with TLSv1.3 session-configuration evidence associated with CVE-2024-2511. The finding is reported as medium-confidence source/config evidence with a "Likely issue" posture. It does not claim FixVibe ran the TLS server, proved the repository artifact is deployed, or reproduced memory growth.

Verification Boundary

This check is static-only. FixVibe does not send denial-of-service traffic, run stress handshakes, or attempt to grow server memory. Treat the result as a prompt to verify the deployed TLS runtime, package provenance, container layer, and session configuration before closing or escalating the issue.