CVE-2026-12413

IKEv2 Denial of Service via malformed fragmentation

Published Jul 2, 2026 CVSS 3.1 · 7.5 High EPSS < 1% KEV · Not listed
Description
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.

Remediation

Vendor Solution

Upgrade to libreswan 5.3.1 or later. Patches for libreswan 4.15 and 5.3 are available at https://libreswan.org


Vendor Workaround

If fragmentation is not needed, fragmentation=no can be added to all IKEv2 configurations. If fragmentation is needed, no workaround is possible and the fix needs to be applied.

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Libreswan
Libreswan libreswan
Vendors & Products Libreswan
Libreswan libreswan
Type Values Removed Values Added
Description 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.
Title IKEv2 Denial of Service via malformed fragmentation
Weaknesses CWE-193
CWE-617
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
libreswan
Published
Updated
Jul 7, 2026, 5:02 PM
Reserved
Jun 16, 2026, 3:52 PM
Status
Analyzed
Published
Jul 2, 2026, 10:16 PM
Modified
Oct 25, 2026, 9:10 PM
Severity
Important
Public date
Jun 24, 2026, 12:00 AM