CVE-2026-50722: high-severity vulnerability in The Libreswan Project libreswan
IKEv2 Denial of Service via RSA-SHA1 (PKCS#1 RSASSA-PKCS1-v1_5) authentication payload
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21Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 7.5epss 0.3%
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.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Affected products
The Libreswan Project · libreswanRelated CVEs — The Libreswan Project libreswan
In the same product, most dangerous first.
CVE-2026-77206HIGHIKEv2 pre-authentication Null Pointer Dereference in EAP codeEPSS 0.7%CVE-2026-12413HIGHIKEv2 Denial of Service via malformed fragmentationEPSS 0.6%CVE-2026-14957HIGHFIPS mode assertion failure via malicious CERT payloadEPSS 0.5%CVE-2026-77207HIGHNull Pointer Dereference in PKCS#7 bundle with no certificatesEPSS 0.5%CVE-2026-94453HIGHIKEv2 Use-After-Free bug when using IKE-over-TCPEPSS 0.5%CVE-2026-50721HIGHIKEv1 Denial of Service via RSA-SHA1 (PKCS#1 Version 1.5 Encrypted) authentication payloadEPSS 0.4%