جزئیات آسیب‌پذیری

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.

• https://libreswan.org/security/CVE-2026-50722/CVE-2026-50722.txt vendor-advisory
• https://libreswan.org/security/CVE-2026-50722/ patch
• https://libreswan.org/security/CVE-2026-50721/CVE-2026-50721.txt related
• https://www.rfc-editor.org/rfc/rfc8017 technical-description