CVE-2026-50721 Affecting libreswan package, versions <0:5.3.2-1.el10_2


Severity

Recommended
high

Based on Rocky Linux security rating.

Threat Intelligence

EPSS
0.39% (31st percentile)

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  • Snyk IDSNYK-ROCKY10-LIBRESWAN-18384841
  • published29 Jul 2026
  • disclosed2 Jul 2026

Introduced: 2 Jul 2026

CVE-2026-50721  (opens in a new tab)

How to fix?

Upgrade Rocky-Linux:10 libreswan to version 0:5.3.2-1.el10_2 or higher.
This issue was patched in RLSA-2026:46398.

NVD Description

Note: Versions mentioned in the description apply only to the upstream libreswan package and not the libreswan package as distributed by Rocky-Linux. See How to fix? for Rocky-Linux:10 relevant fixed versions and status.

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.

CVSS Base Scores

version 3.1