OpenSSL Session Cache Unbounded MEM Growth TLSv1.3 via SSL_OP_NO_TICKET (3.2)
CVE-2024-2511 Published on April 8, 2024
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
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.
Vulnerability Analysis
CVE-2024-2511 can be exploited with network access, and does not require authorization privileges or user interaction. This vulnerability is consided to have a high level of attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity, and a high impact on availability.
Weakness Type
What is a Stack Exhaustion Vulnerability?
The product manages a group of objects or resources and performs a separate memory allocation for each object, but it does not properly limit the total amount of memory that is consumed by all of the combined objects.
CVE-2024-2511 has been classified to as a Stack Exhaustion vulnerability or weakness.
Products Associated with CVE-2024-2511
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Affected Versions
OpenSSL:- Version 3.2.0 and below 3.2.2 is affected.
- Version 3.1.0 and below 3.1.6 is affected.
- Version 3.0.0 and below 3.0.14 is affected.
- Version 1.1.1 and below 1.1.1y is affected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.