CVE-2026-50722

NameCVE-2026-50722
DescriptionLibreswan, 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.
SourceCVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
libreswan (PTS)bullseye4.3-1+deb11u4vulnerable
bullseye (security)4.3-1+deb11u3vulnerable
bookworm4.10-2+deb12u1vulnerable
trixie5.2-2.2vulnerable
forky, sid5.2-2.4vulnerable

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
libreswansource(unstable)(unfixed)

Notes

https://libreswan.org/security/CVE-2026-50722/CVE-2026-50722.txt
Patches: https://libreswan.org/security/CVE-2026-50722/

Search for package or bug name: Reporting problems