CVE-2024-2511: Unbounded memory growth with session handling in TLSv1.3
Issue summary: Some non-default TLS server configurations can cause unbounded memory growth when processing TLSv1.3 sessions
Other sources
Some non-default TLS server configurations can cause unbounded memory growth when processing TLSv1.3 sessions Impact summary: An attacker may exploit certain server configurations to trigger unbounded memory growth that would lead to a Denial of Service This problem can occur in TLSv1.3 if the non-default SSLOPNOTICKET option is being used (but not if earlydata support is also configured and the default anti-replay protection is in use). In this case, under certain conditions, the session cache can get into an incorrect state and it will fail to flush properly as it fills. The session cache will continue to grow in an unbounded manner. A malicious client could deliberately create the scenario for this failure to force a Denial of Service. It may also happen by accident in normal operation. This issue only affects TLS servers supporting TLSv1.3. It does not affect TLS clients. The FIPS modules in 3.2, 3.1 and 3.0 are not affected by this issue. OpenSSL 1.0.2 is also not affected by this issue.
— F5
Unbounded memory growth with session handling in TLSv1.3
— Microsoft
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
redhat/OpenSSLto a version that resolves this vulnerability.Fixed in 3.2.2 - Upgrade
Upgrade
redhat/OpenSSLto a version that resolves this vulnerability.Fixed in 3.1.6 - Upgrade
Upgrade
redhat/OpenSSLto a version that resolves this vulnerability.Fixed in 3.0.14 - Upgrade
Upgrade
redhat/OpenSSLto a version that resolves this vulnerability.Fixed in 1.1.1 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 38.0.72.2-1 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 3.3.0-1 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 20.14.0-1 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 1.0.1-6 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in - - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 20240524git3e722403cd16-8 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 1.1.1k-30 - Upgrade
Upgrade
debian/opensslto a version that resolves this vulnerability.Fixed in 1.1.1w-0+deb11u8Fixed in 3.0.20-1~deb12u2Fixed in 3.5.6-1~deb13u2Fixed in 3.5.7-1~deb13u2Fixed in 3.6.3-1Fixed in 3.6.4-1 - Configuration
This issue can occur in TLSv1.3 if the non-default SSL_OP_NO_TICKET option is being used. Configure your TLS server so SSL_OP_NO_TICKET is not enabled (or otherwise avoid using it in TLSv1.3 server configurations).
OpenSSL TLS server (TLSv1.3) SSL_OP_NO_TICKET = disable (do not use) - Configuration
For the TLSv1.3 case affected by SSL_OP_NO_TICKET, the issue does not occur if early_data support is also configured and the default anti-replay protection is in use. Enable early_data support (when appropriate) together with default anti-replay protection to avoid the unbounded memory growth condition.
OpenSSL TLS server (TLSv1.3) early_data support = enable (if applicable)
Event History
Frequently Asked Questions
What is the severity of CVE-2024-2511?
CVE-2024-2511 is classified as a high severity vulnerability due to its potential to cause a Denial of Service.
How do I fix CVE-2024-2511?
To address CVE-2024-2511, upgrade your OpenSSL version to any of the remedial versions listed in the vulnerability report.
What are the affected OpenSSL versions for CVE-2024-2511?
CVE-2024-2511 affects specific versions of OpenSSL prior to the stated remedial releases.
Can CVE-2024-2511 be exploited remotely?
Yes, CVE-2024-2511 can be exploited by remote attackers under certain server configurations.
Is there a workaround for CVE-2024-2511?
While upgrading is the best remediation, consider reviewing and adjusting your TLS server configurations as a temporary measure.