GHSA-2Q27-MPM9-44M4
Vulnerability from github – Published: 2026-08-25 15:32 – Updated: 2026-08-25 15:32Issue 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.
{
"affected": [],
"aliases": [
"CVE-2026-63074"
],
"database_specific": {
"cwe_ids": [
"CWE-770"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-08-25T13:19:26Z",
"severity": "MODERATE"
},
"details": "Issue summary: The OpenSSL Certificate Management Protocol (CMP) caches\nadditional certificates (extraCerts) sent in a CMP message, but never expunges\nthem (for instance if they are invalid). If a server reuses an OSSL_CMP_CTX\nfrequently, this cache of extraCerts may grow unboundedly, and a malicious\nclient may flood a CMP server with requests driving this growth.\n\nImpact summary: Users utilizing a CMP server that reuses a single OSSL_CMP_CTX\nfor the lifetime of a server process may observe unbounded memory growth in the\nevent a malicious client repeatedly sends requests containing unique extra\ncertificates, which may lead to OOM conditions.\n\nCWE: CWE-770: Allocation of Resources Without Limits or Throttling\n\nDescription: If a remote user sends CMP messages to a server with a list of\nextraCerts and the message is rejected, the extraCerts from the message remains\nin the server contexts untrusted certificate stack. This exposes servers with\nlong lived ctx objects to Denial of Service attacks in which an attacker sends\nmessages intending to be rejected with a large list of additional certificates\nrepeatedly, forcing the server to store them indefinitely.\n \nThe issue was fixed by removing the added extra certs if the message is\nrejected, using the same method as when the context is configured to not do\ncaching at all.\n\nFIPS impact: no\nAs the CMP code lives outside the FIPS module boundary, no FIPS\nmodules are affected by this CVE.",
"id": "GHSA-2q27-mpm9-44m4",
"modified": "2026-08-25T15:32:59Z",
"published": "2026-08-25T15:32:58Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-63074"
},
{
"type": "WEB",
"url": "https://github.com/openssl/openssl/commit/01e567978a55fba18142a230380c31296049fae7"
},
{
"type": "WEB",
"url": "https://github.com/openssl/openssl/commit/21a5d9658b0c66daace60e10ea18ff32a448de9f"
},
{
"type": "WEB",
"url": "https://github.com/openssl/openssl/commit/74ae7f6df47a5767c1010b88c47507dfc5b32c46"
},
{
"type": "WEB",
"url": "https://github.com/openssl/openssl/commit/75360af9650d4e0c82ba0050c5c9912cd79e54af"
},
{
"type": "WEB",
"url": "https://github.com/openssl/openssl/commit/f636f9ca0fa1bae5b42f9e787f025c96fb09c43a"
},
{
"type": "WEB",
"url": "https://openssl-library.org/news/secadv/20260825.txt"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
}
]
}
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.