CVE-2026-50722

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.

Score

CVSS 3.1 8.1 High

Status

Analyzed - d42dc95b-23f1-4e06-9076-20753a0fb0df

Published

2026-07-02

Last modified

2026-10-25

Weaknesses

CWE-347, CWE-617

Affected products

• Libreswan (Libreswan)
• Libreswan (The Libreswan Project)

References

• https://libreswan.org/security/CVE-2026-50722/CVE-2026-50722.txt
• https://libreswan.org/security/CVE-2026-50722/
• https://libreswan.org/security/CVE-2026-50721/CVE-2026-50721.txt
• https://www.rfc-editor.org/rfc/rfc8017