GHSA-R3HF-PF7X-WGQG
Vulnerability from github – Published: 2026-08-25 15:32 – Updated: 2026-08-25 15:32Issue summary: OpenSSL CMP password based protection verification only checks whether the protectionAlg parameter was not NULL and not its ASN.1 type, before treating it as a PBMParameter. A crafted message can contain a parameter of a different type, which is then dereferenced as an invalid pointer.
Impact summary: A remote, unauthenticated attacker can crash an application acting as a CMP server that accepts PBM-protected messages, or a CMP client talking to a malicious or intercepted CMP server, resulting in a Denial of Service.
CWE: CWE-476: NULL Pointer Dereference
Description: When verifying the password-based MAC protection of a CMP message, OpenSSL library reads the protectionAlg algorithm parameter with X509_ALGOR_get0(), which returns both the parameter type and its value pointer. The value is then cast to an ASN1_STRING and treated as the expected PBMParameter after only checking that pointer is not NULL. The parameter type returned by X509_ALGOR_get0() was never consulted.
This happens during protection verification, before any MAC is computed, so no knowledge of the PBM shared secret is required; the only precondition is that PBM verification is reachable. On the server side this is reached from OSSL_CMP_SRV_process_request() for any application that stands up a CMP server accepting PBM-protected messages, and on the client side from CMP response validation against a malicious or on-path (MITM) server. The reliable consequence is a denial of service; there is no memory disclosure, no controlled memory write, and no path to code execution. CMP is a specialized feature that an application must explicitly enable.
FIPS impact: no As the CMP code lives outside the FIPS module boundary, no FIPS modules are affected by this CVE.
{
"affected": [],
"aliases": [
"CVE-2026-63076"
],
"database_specific": {
"cwe_ids": [
"CWE-476"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-08-25T13:19:26Z",
"severity": "HIGH"
},
"details": "Issue summary: OpenSSL CMP password based protection verification only\nchecks whether the protectionAlg parameter was not NULL and not its\nASN.1 type, before treating it as a PBMParameter. A crafted message can\ncontain a parameter of a different type, which is then dereferenced as an\ninvalid pointer.\n\nImpact summary: A remote, unauthenticated attacker can crash an application\nacting as a CMP server that accepts PBM-protected messages, or a CMP client\ntalking to a malicious or intercepted CMP server, resulting in a Denial of\nService.\n\nCWE: CWE-476: NULL Pointer Dereference\n\nDescription: When verifying the password-based MAC protection of a CMP\nmessage, OpenSSL library reads the protectionAlg algorithm parameter with\nX509_ALGOR_get0(), which returns both the parameter type and its value\npointer. The value is then cast to an ASN1_STRING and treated as the\nexpected PBMParameter after only checking that pointer is not NULL. The\nparameter type returned by X509_ALGOR_get0() was never consulted.\n\nThis happens during protection verification, before any MAC is computed, so\nno knowledge of the PBM shared secret is required; the only precondition is\nthat PBM verification is reachable. On the server side this is reached from\nOSSL_CMP_SRV_process_request() for any application that stands up a CMP\nserver accepting PBM-protected messages, and on the client side from CMP\nresponse validation against a malicious or on-path (MITM) server. The\nreliable consequence is a denial of service; there is no memory disclosure,\nno controlled memory write, and no path to code execution. CMP is a\nspecialized feature that an application must explicitly enable.\n\nFIPS impact: no\nAs the CMP code lives outside the FIPS module boundary, no FIPS modules\nare affected by this CVE.",
"id": "GHSA-r3hf-pf7x-wgqg",
"modified": "2026-08-25T15:32:59Z",
"published": "2026-08-25T15:32:58Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-63076"
},
{
"type": "WEB",
"url": "https://github.com/openssl/openssl/commit/37882aa2e0256e1072442a8f62f7db45b995c45b"
},
{
"type": "WEB",
"url": "https://github.com/openssl/openssl/commit/a17cc8d612ecff6d94a9b7ca8b5283ddf5ff570e"
},
{
"type": "WEB",
"url": "https://github.com/openssl/openssl/commit/a1f348ccb328c3afbd4ba6883f9b7c813c043259"
},
{
"type": "WEB",
"url": "https://github.com/openssl/openssl/commit/a7af46a92d0ce19a90e669ef56d2576a07924226"
},
{
"type": "WEB",
"url": "https://github.com/openssl/openssl/commit/cdacfff557389abfa9e4615abded2ec984517d6c"
},
{
"type": "WEB",
"url": "https://openssl-library.org/news/secadv/20260825.txt"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
}
]
}
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
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