CVE-2026-50722

Updated on 02 Jul 2026

Severity

5.9 Medium severity

Details

CVSS score
5.9
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

Overview

About vulnerability

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.

Details

Affected product:
AlmaLinux 9.2 ESU , TuxCare 9.6 ESU
Affected packages:
libreswan @ 4.15 (+1 more)

Fixes