GHSA-93PJ-2PMF-2X7P
Vulnerability from github – Published: 2026-07-03 00:31 – Updated: 2026-07-03 00:31Libreswan, via the function RSA_authenticate_hash_signature_raw_rsa(), did not correctly verify the length of the authentication hash when the SIG payload of an IKEv1 packet was encoded using PKCS #1 RSA Encryption as per RFC 2313. A remote attacker can use a variation on the Bleichenbacher attack to forge the SIG payload when small public exponents are being used (e.g., e=3), which could lead to impersonation. Additionally, a remote attacker, by encoding a shorter than expected hash in the SIG payload, could trigger an assertion leading to denial-of-service. The daemon aborts and restarts; continued exploitation causes sustained denial of service. Remote code execution is not possible. X.509 certificate verifications of remote IKE peers are not affected.
{
"affected": [],
"aliases": [
"CVE-2026-50721"
],
"database_specific": {
"cwe_ids": [
"CWE-347"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-07-02T22:16:43Z",
"severity": "HIGH"
},
"details": "Libreswan, via the function RSA_authenticate_hash_signature_raw_rsa(), did not correctly verify the length of the authentication hash when the SIG payload of an IKEv1 packet was encoded using PKCS #1 RSA Encryption as per RFC 2313. A remote attacker can use a variation on the Bleichenbacher attack to forge the SIG payload when small public exponents are being used (e.g., e=3), which could lead to impersonation. Additionally, a remote attacker, by encoding a shorter than expected hash in the SIG payload, could trigger an assertion leading to denial-of-service. The daemon aborts and restarts; continued exploitation causes sustained denial of service. Remote code execution is not possible. X.509 certificate verifications of remote IKE peers are not affected.",
"id": "GHSA-93pj-2pmf-2x7p",
"modified": "2026-07-03T00:31:52Z",
"published": "2026-07-03T00:31:52Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-50721"
},
{
"type": "WEB",
"url": "https://libreswan.org/security/CVE-2026-50721"
},
{
"type": "WEB",
"url": "https://libreswan.org/security/CVE-2026-50721/CVE-2026-50721.txt"
},
{
"type": "WEB",
"url": "https://libreswan.org/security/CVE-2026-50722/CVE-2026-50722.txt"
},
{
"type": "WEB",
"url": "https://www.rfc-editor.org/rfc/rfc2313"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
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