CVE-2024-2511

Description

Issue summary: 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 SSL_OP_NO_TICKET option is being used (but not if early_data 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.

CVSS v3.1 Score

5.9

MEDIUM

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

Weakness Type (CWE)

CWE-1325 CWE-1325

References

Other References

https://github.com/openssl/openssl/commit/7e4d731b1c07201ad9374c1cd9ac5263bdf35bce https://github.com/openssl/openssl/commit/b52867a9f618bb955bed2a3ce3db4d4f97ed8e5d https://github.com/openssl/openssl/commit/e9d7083e241670332e0443da0f0d4ffb52829f08 https://github.openssl.org/openssl/extended-releases/commit/5f8d25770ae6437db119dfc951e207271a326640 https://www.openssl.org/news/secadv/20240408.txt http://www.openwall.com/lists/oss-security/2024/04/08/5 https://github.com/openssl/openssl/commit/7e4d731b1c07201ad9374c1cd9ac5263bdf35bce https://github.com/openssl/openssl/commit/b52867a9f618bb955bed2a3ce3db4d4f97ed8e5d https://github.com/openssl/openssl/commit/e9d7083e241670332e0443da0f0d4ffb52829f08 https://github.openssl.org/openssl/extended-releases/commit/5f8d25770ae6437db119dfc951e207271a326640

Frequently Asked Questions

What is CVE-2024-2511? +

Issue summary: 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 SSL_OP_NO_TICKET option is being used (but not if early_data 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. It has a CVSS v3.1 base score of 5.9 (MEDIUM).

How severe is CVE-2024-2511? +

CVE-2024-2511 has a CVSS v3.1 score of 5.9 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

How do I check if I'm vulnerable to CVE-2024-2511? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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