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OpenSSL CVE-2026-63074

| EUVDEUVD-2026-65484 MEDIUM
Allocation of Resources Without Limits or Throttling (CWE-770)
2026-08-25 openssl-security@openssl.org GHSA-2q27-mpm9-44m4
OpenSSL Denial Of Service Red Hat Suse
5.9
CVSS 3.1 · Vendor: openssl
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Severity by source

Vendor (openssl) PRIMARY
5.9 MEDIUM
AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
vuln.today AI
5.9 MEDIUM

AC:H reflects the specific long-lived context deployment requirement; PR:N because no credentials are needed to submit CMP messages; only availability is impacted.

3.1 AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
4.0 AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
SUSE
5.3 MEDIUM
AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Red Hat
7.5 LOW
qualitative

Primary rating from Vendor (openssl).

CVSS VectorVendor: openssl

Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

Lifecycle Timeline

6
Source Code Evidence Fetched
Aug 25, 2026 - 15:46 vuln.today
Analysis Generated
Aug 25, 2026 - 15:46 vuln.today
CVSS changed
Aug 25, 2026 - 15:22 NVD
5.9 (None) 5.9 (MEDIUM)
Patch available
Aug 25, 2026 - 15:01 EUVD
CVE Published
Aug 25, 2026 - 13:19 cve.org
MEDIUM 5.9
CVE Published
Aug 25, 2026 - 13:19 cve.org
UNKNOWN (no severity yet)

DescriptionCVE.org

Issue summary: The OpenSSL Certificate Management Protocol (CMP) caches additional certificates (extraCerts) sent in a CMP message, but never expunges them (for instance if they are invalid). If a server reuses an OSSL_CMP_CTX frequently, this cache of extraCerts may grow unboundedly, and a malicious client may flood a CMP server with requests driving this growth.

Impact summary: Users utilizing a CMP server that reuses a single OSSL_CMP_CTX for the lifetime of a server process may observe unbounded memory growth in the event a malicious client repeatedly sends requests containing unique extra certificates, which may lead to OOM conditions.

CWE: CWE-770: Allocation of Resources Without Limits or Throttling

Description: If a remote user sends CMP messages to a server with a list of extraCerts and the message is rejected, the extraCerts from the message remains in the server contexts untrusted certificate stack. This exposes servers with long lived ctx objects to Denial of Service attacks in which an attacker sends messages intending to be rejected with a large list of additional certificates repeatedly, forcing the server to store them indefinitely.

The issue was fixed by removing the added extra certs if the message is rejected, using the same method as when the context is configured to not do caching at all.

FIPS impact: no As the CMP code lives outside the FIPS module boundary, no FIPS modules are affected by this CVE.

AnalysisAI

Unbounded memory growth in OpenSSL's Certificate Management Protocol (CMP) implementation enables unauthenticated remote attackers to exhaust server memory by repeatedly sending rejected CMP messages containing large extraCerts lists. Affected are OpenSSL 3.0.x before 3.0.22, 3.4.x before 3.4.7, 3.5.x before 3.5.8, 3.6.x before 3.6.4, and 4.0.x before 4.0.2 - but only when the CMP server shares a single long-lived OSSL_CMP_CTX across requests. …

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Vulnerability AssessmentAI

Exploitation Exploitation requires three concurrent conditions: (1) the target exposes a CMP (Certificate Management Protocol, RFC 4210) endpoint implemented using a vulnerable OpenSSL version; (2) the CMP server is architecturally designed to reuse a single OSSL_CMP_CTX object for the lifetime of the server process - servers that create a fresh context per connection or per request are immune because the certificate stack is discarded after each use regardless of patching; and (3) the attacker can reach the CMP endpoint over the network. … Additional conditions and limiting factors are described in the full assessment.
Risk Assessment The CVSS 5.9 (Medium) score and AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H vector accurately reflect the bounded real-world risk. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in.
Exploit Scenario Full exploit scenario with step-by-step reproduction available after sign-in.
Remediation Upgrade to the patched OpenSSL releases corresponding to your branch: 3.0.22, 3.4.7, 3.5.8, 3.6.4, or 4.0.2. … Detailed patch versions, workarounds, and compensating controls in full report.
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Vendor StatusVendor

SUSE

Severity: Moderate
Product Status
Container suse/ltss/sle15.5/sle15:15.5-8.67 Affected
Container suse/ltss/sle15.6/bci-base-fips:15.6-35.94 Affected
Container suse/ltss/sle15.6/sle15:15.6-5.86 Affected
Container suse/sl-micro/6.0/baremetal-os-container:latest Affected
Container suse/sl-micro/6.0/base-os-container:latest Container suse/sl-micro/6.1/base-os-container:latest Image SL-Micro Image SL-Micro-Base Image SL-Micro-Base-RT Image SL-Micro-Base-RT-SelfInstall Image SL-Micro-Base-RT-encrypted Image SL-Micro-Base-SelfInstall Image SL-Micro-Base-encrypted Image SL-Micro-Base-qcow Image SL-Micro-Default Image SL-Micro-Default-SelfInstall Image SL-Micro-Default-encrypted Image SL-Micro-Default-qcow Affected

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CVE-2026-63074 vulnerability details – vuln.today
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