Unbounded Memory Growth in TLSv1.3 Sessions Due to Non-Default Server Configurations
CVE-2024-2511

5.9MEDIUM

Key Information:

Vendor

OpenSSL

Status
Vendor
CVE Published:
8 April 2024

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.

Affected Version(s)

OpenSSL 3.2.0 < 3.2.2

OpenSSL 3.1.0 < 3.1.6

OpenSSL 3.0.0 < 3.0.14

References

CVSS V3.1

Score:
5.9
Severity:
MEDIUM
Confidentiality:
None
Integrity:
None
Availability:
None
Attack Vector:
Network
Attack Complexity:
High
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

Manish Patidar (Hewlett Packard Enterprise)
Matt Caswell
.
CVE-2024-2511 : Unbounded Memory Growth in TLSv1.3 Sessions Due to Non-Default Server Configurations