CVEvulnerability

CVE-2026-50721

5.9 MEDIUM Published 2026-07-02 Modified 2026-10-25 Official page ↗
Status
Analyzed
Published
2026-07-02
Last modified
2026-10-25
Assigner
d42dc95b-23f1-4e06-9076-20753a0fb0df
CVSS 3.1 (d42dc95b-23f1-4e06-9076-20753a0fb0df)
8.1 HIGH — CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS 3.1 ([email protected])
5.9 MEDIUM — CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Weaknesses
CWE-347, CWE-617

Description

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.

Affected configurations

• libreswan libreswan (< 5.3.1)

Related

Weakness · CWE (2)

  • CWE-347 Improper Verification of Cryptographic Signature weakness
  • CWE-617 Reachable Assertion weakness

References