CMP Indefinite Cache Growth of ExtraCerts

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-63074
StatePUBLISHED
Assigneropenssl
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-25 13:19:26 UTC
Updated2026-09-11 21:16:58 UTC
DescriptionIssue 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.

Risk And Classification

Primary CVSS: v3.1 5.9 MEDIUM from ADP

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

EPSS: 0.004880000 probability, percentile 0.400250000 (date 2026-08-30)

Problem Types: CWE-770 | CWE-770 CWE-770 Allocation of Resources Without Limits or Throttling

VersionSourceTypeScoreSeverityVector
3.1ADPDECLARED5.9MEDIUMCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
3.1134c704f-9b21-4f2e-91b3-4a467353bcc0Secondary5.9MEDIUMCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS v3.1 Breakdown

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

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

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Application Openssl Openssl All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA OpenSSL OpenSSL affected 4.0.0 4.0.2 semver Not specified
CNA OpenSSL OpenSSL affected 3.6.0 3.6.4 semver Not specified
CNA OpenSSL OpenSSL affected 3.5.0 3.5.8 semver Not specified
CNA OpenSSL OpenSSL affected 3.4.0 3.4.7 semver Not specified
CNA OpenSSL OpenSSL affected 3.0.0 3.0.22 semver Not specified

References

ReferenceSourceLinkTags
github.com/openssl/openssl/commit/f636f9ca0fa1bae5b42f9e787f025c96fb09c43a [email protected] github.com Patch
openssl-library.org/news/secadv/20260825.txt [email protected] openssl-library.org Vendor Advisory
github.com/openssl/openssl/commit/74ae7f6df47a5767c1010b88c47507dfc5b32c46 [email protected] github.com Patch
github.com/openssl/openssl/commit/01e567978a55fba18142a230380c31296049fae7 [email protected] github.com Patch
github.com/openssl/openssl/commit/75360af9650d4e0c82ba0050c5c9912cd79e54af [email protected] github.com Patch
github.com/openssl/openssl/commit/21a5d9658b0c66daace60e10ea18ff32a448de9f [email protected] github.com Patch
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: Pavоl Žáčik (Red Hat) (en)

CNA: Neil Horman (en)

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