Improper Verification of Cryptographic Signature Affecting libreswan-minimal package, versions <0:5.3.2-1.el10_2


Severity

Recommended
medium

Based on Red Hat Enterprise Linux security rating.

Threat Intelligence

EPSS
0.35% (28th percentile)

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  • Snyk IDSNYK-RHEL10-LIBRESWANMINIMAL-18339639
  • published28 Jul 2026
  • disclosed24 Jun 2026

Introduced: 24 Jun 2026

CVE-2026-50722  (opens in a new tab)
CWE-347  (opens in a new tab)

How to fix?

Upgrade RHEL:10 libreswan-minimal to version 0:5.3.2-1.el10_2 or higher.
This issue was patched in RHSA-2026:46398.

NVD Description

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

Libreswan, via the function RSA_authenticate_hash_signature_pkcs1_1_5_rsa(), did not correctly verify the DER encoding of the ASN.1 digest when the IKEv2 AUTH payload was encoded using RSASSA-PKCS1-v1_5 (RFC 8017). A remote attacker can use a variation on the Bleichenbacher attack to forge the AUTH payload when small public exponents are used (e.g., e=3), leading to impersonation. Additionally, a remote attacker, by encoding a shorter than expected hash in the AUTH 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 the remote IKE peer are not affected.

CVSS Base Scores

version 3.1