Threat Intelligence / CVE / CVE-2026-50721

CVE-2026-50721

CVSS 7.5 (HIGH) · Priority 3.8/10 · Published 2026-07-02

As of 2026-07-02, CVE-2026-50721 is a CVSS 7.5 (HIGH-severity) vulnerability. Threadlinqs Intelligence tracks 0 threats exploiting it.

Last updated: 2026-07-02

Libreswan, via the function RSA_authenticate_hash_signature_raw_rsa(), did not correctly verify the length of the authentication hash when the SIG payload of an IKEv1 packet was encoded using PKCS #1 RSA Encryption as per RFC 2313. A remote attacker can use a variation on the Bleichenbacher attack to forge the SIG payload when small public exponents are being used (e.g., e=3), which could lead to impersonation. Additionally, a remote attacker, by encoding a shorter than expected hash in the SIG 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 remote IKE peers are not affected.

CVSS v3 vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Weaknesses (CWE)

CWE-347, CWE-617

References

Full detection coverage & IOCs for threats exploiting CVE-2026-50721 are available via the Threadlinqs MCP server (Purple tier). View plans →

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Enriched from CVE.org, NVD (this product uses the NVD API but is not endorsed or certified by the NVD), FIRST EPSS, CISA KEV, and GitHub Security Advisories.