CVE-2024-2511

Unbounded memory growth with session handling in TLSv1.3

MEDIUM
5.9
CVSS Score
Published: April 8, 2024 at 01:51 PM UTC
Updated: October 15, 2026 at 01:17 AM UTC
34 products affected across 2 vendorsOpenSSLSIMATIC S7-1500 CPU 1518-4 Pn /dp MFP FirmwareSiplus S7-1500 CPU 1518-4 Pn /dp MFP Firmware

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Severity
MEDIUM5.9
Exploit prediction
EPSS 52%
SSVC
No known exploit

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Affected range stops below 1.1.1y, so it looks safe — our inference, not a vendor statement
Affected range stops below 3.0.14, so it looks safe — our inference, not a vendor statement
Affected range stops below 3.1.6, so it looks safe — our inference, not a vendor statement
Affected range stops below 3.2.2, so it looks safe — our inference, not a vendor statement
v < V8.2
Affected range stops below V8.2, so it looks safe — our inference, not a vendor statement
v < V8.2
Affected range stops below V8.2, so it looks safe — our inference, not a vendor statement
v < V3.1
Affected range stops below V3.1, so it looks safe — our inference, not a vendor statement
v < V8.2
Affected range stops below V8.2, so it looks safe — our inference, not a vendor statement
v < V8.2
Affected range stops below V8.2, so it looks safe — our inference, not a vendor statement
v < V8.2
Affected range stops below V8.2, so it looks safe — our inference, not a vendor statement
v < V8.2
Affected range stops below V8.2, so it looks safe — our inference, not a vendor statement
v < V8.2
Affected range stops below V8.2, so it looks safe — our inference, not a vendor statement
v < V8.2
Affected range stops below V8.2, so it looks safe — our inference, not a vendor statement

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

5.9MEDIUMCISA-ADP
Attack Vector
NETWORK
Complexity
HIGH
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-1325

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