IKEv2 Denial of Service via malformed fragmentation

MITRE NVD CVE.ORG JSON API Print: PDF PDF

Summary

CVECVE-2026-12413
StatePUBLISHED
Assignerlibreswan
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-07-02 22:16:42 UTC
Updated2026-07-08 18:52:42 UTC
DescriptionAn 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.

Risk And Classification

Primary CVSS: v3.1 7.5 HIGH from d42dc95b-23f1-4e06-9076-20753a0fb0df

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

EPSS: 0.005970000 probability, percentile 0.444240000 (date 2026-07-10)

Problem Types: CWE-193 | CWE-617 | CWE-193 Off-by-one Error | CWE-617 Reachable Assertion

VersionSourceTypeScoreSeverityVector
3.1d42dc95b-23f1-4e06-9076-20753a0fb0dfSecondary7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
3.1CNACVSS7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

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

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Application Libreswan Libreswan All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA The Libreswan Project Libreswan affected 4.6 5.3 semver Not specified
CNA The Libreswan Project Libreswan unaffected 5.3.1 semver Not specified

References

ReferenceSourceLinkTags
libreswan.org/security/CVE-2026-12413/CVE-2026-12413.txt d42dc95b-23f1-4e06-9076-20753a0fb0df libreswan.org Vendor Advisory, Mitigation
libreswan.org/security/CVE-2026-12413 d42dc95b-23f1-4e06-9076-20753a0fb0df libreswan.org Vendor Advisory
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: Hu Xinyao (en)

Additional Advisory Data

SourceTimeEvent
CNA2026-06-16T00:00:00.000ZLibreswan notified of the issue via [email protected]
CNA2026-06-16T00:00:00.000ZAdvanced notice given to supported customers and distributions
CNA2026-06-24T00:00:00.000ZPublic announcement and release of libreswan 5.3.1

Solutions

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

Workarounds

CNA: 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.

© CVE.report 2026 |

Use of this information constitutes acceptance for use in an AS IS condition. There are NO warranties, implied or otherwise, with regard to this information or its use. Any use of this information is at the user's risk. It is the responsibility of user to evaluate the accuracy, completeness or usefulness of any information, opinion, advice or other content. EACH USER WILL BE SOLELY RESPONSIBLE FOR ANY consequences of his or her direct or indirect use of this web site. ALL WARRANTIES OF ANY KIND ARE EXPRESSLY DISCLAIMED. This site will NOT BE LIABLE FOR ANY DIRECT, INDIRECT or any other kind of loss.

CVE, CWE, and OVAL are registred trademarks of The MITRE Corporation and the authoritative source of CVE content is MITRE's CVE web site. This site includes MITRE data granted under the following license.

Free CVE JSON API cve.report/api

CVE.report and Source URL Uptime Status status.cve.report