Improper Verification of Cryptographic Signature Affecting libreswan/libreswan package, versions [,5.3.1)
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-UNMANAGED-LIBRESWANLIBRESWAN-17807923
- published3 Jul 2026
- disclosed3 Jul 2026
- creditUnknown
Introduced: 3 Jul 2026
CVE-2026-50722 (opens in a new tab)How to fix?
Upgrade libreswan/libreswan to version 5.3.1 or higher.
Overview
Affected versions of this package are vulnerable to Improper Verification of Cryptographic Signature in the RSA_authenticate_hash_signature_pkcs1_1_5_rsa function. An attacker can cause the daemon to abort and restart by sending a specially crafted IKEv2 AUTH payload with a shorter than expected hash, resulting in sustained service disruption through repeated exploitation.
Workaround
This vulnerability can be mitigated by configuring authby=ecdsa or authby=rsa-sha2 (or both via authby=ecdsa,rsa-sha2) to disallow the fallback of RSA PKCS#1 1.5. The leftauth= and rightauth= settings can be updated similarly if those are in use instead of authby.