CVE-2026-12413
HighCVSS 7.5Exploitation Probability (EPSS)
Low risk44th percentile - higher than 44% of all known CVEs
Summary
An invalidly formatted IKEv2 fragment causes the Libreswan pluto daemon to crash and restart. An off-by-one error in the PASSERT assertion leads to daemon abort.
Risk Assessment
An attacker can exploit this vulnerability to cause a Denial of Service (DoS) on the VPN server, forcing continuous restarts and preventing legitimate IKEv2 connections.
Recommendation
Immediately update Libreswan to a patched version. As a temporary workaround, disable IKEv2 fragmentation by setting 'fragmentation=no' in connection configuration.
Other vulnerabilities in Libreswan
See all- CVE-2016-5391High
Libreswan before 3.18 allows remote attackers to cause a denial of service via NULL pointer dereference, leading to a restart of the pluto daemon.
- CVE-2016-5361High
In libreswan before version 3.17, there is an issue with retransmission in initial responder states, allowing remote attackers to cause a denial of service (traffic amplification) via a spoofed UDP packet.
- CVE-2016-3071High
Libreswan version 3.16 may allow remote attackers to cause a denial of service (daemon restart) via an IKEv2 aes_xcbc transform.
- CVE-2026-50722High
In Libreswan, the function RSA_authenticate_hash_signature_pkcs1_1_5_rsa() incorrectly verifies the DER encoding of the ASN.1 digest when the IKEv2 AUTH payload uses RSASSA-PKCS1-v1_5. A remote attacker can exploit a Bleichenbacher-style attack to forge the AUTH payload, leading to impersonation, or trigger an assertion causing denial-of-service.
- CVE-2026-50721High
Libreswan has a vulnerability in the RSA_authenticate_hash_signature_raw_rsa() function that incorrectly verifies the authentication hash length in IKEv1 packets using PKCS #1 RSA encoding. A remote attacker can forge the SIG payload via a Bleichenbacher-style attack, leading to impersonation, or cause denial-of-service by sending a shorter hash.
- CVE-2023-38711Medium
An issue was discovered in Libreswan before version 4.12, occurring when an IKEv1 Quick Mode connection configured with ID_IPV4_ADDR or ID_IPV6_ADDR receives an IDcr payload with ID_FQDN. This causes a NULL pointer dereference, resulting in a crash and restart of the pluto daemon.
- CVE-2023-38710Medium
An issue was discovered in Libreswan before version 4.12 related to IKEv2 Child SA REKEY packets containing an invalid IPsec protocol ID of 0 or 1. This results in an error notify INVALID_SPI being sent back, causing the pluto daemon to crash.
Original NVD description (English source)
An invalidly formatted IKEv2 fragment causes the Libreswan pluto daemon to crash and restart. Continued exploitation would cause a denial of service. The function reassemble_v2_incoming_fragments() would ignore unknown outer payloads but still store these in a fixed size array msg_digest.digest[PAYLIMIT]. An off-by-one error in the assertion PASSERT(logger, md->digest_roof < elemsof(md->digest)) causes the daemon to abort. No remote code execution is possible. Any configuration that allows IKEv2 connections that do not set fragmentation=no are vulnerable. IKEv1 is not affected.