CVE-2026-12413: Off-by-one Error in The Libreswan Project libreswan
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.
AI Analysis
Technical Summary
The Libreswan pluto daemon contains an off-by-one error in the function reassemble_v2_incoming_fragments() that handles IKEv2 fragmented packets. When an invalidly formatted IKEv2 fragment with unknown outer payloads is received, the daemon stores these payloads in a fixed-size array msg_digest.digest[PAYLIMIT] without proper bounds checking. The assertion PASSERT(logger, md->digest_roof < elemsof(md->digest)) fails due to this off-by-one error, causing the daemon to abort and restart. This leads to a denial of service condition. The vulnerability does not permit remote code execution. Only configurations that allow IKEv2 fragmentation (fragmentation not disabled) are vulnerable; IKEv1 is unaffected.
Potential Impact
Successful exploitation causes the Libreswan pluto daemon to crash and restart repeatedly, resulting in a denial of service. There is no impact on confidentiality or integrity, and remote code execution is not possible. Systems configured to allow IKEv2 fragmentation are vulnerable, potentially disrupting VPN connectivity or other services relying on the daemon.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, mitigate by configuring Libreswan to disable IKEv2 fragmentation (set fragmentation=no) to prevent triggering the vulnerability. Monitor vendor communications for official patches or updates.
CVE-2026-12413: Off-by-one Error in The Libreswan Project libreswan
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.
CVSS v3.1
Score 7.5high
Affected software
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AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The Libreswan pluto daemon contains an off-by-one error in the function reassemble_v2_incoming_fragments() that handles IKEv2 fragmented packets. When an invalidly formatted IKEv2 fragment with unknown outer payloads is received, the daemon stores these payloads in a fixed-size array msg_digest.digest[PAYLIMIT] without proper bounds checking. The assertion PASSERT(logger, md->digest_roof < elemsof(md->digest)) fails due to this off-by-one error, causing the daemon to abort and restart. This leads to a denial of service condition. The vulnerability does not permit remote code execution. Only configurations that allow IKEv2 fragmentation (fragmentation not disabled) are vulnerable; IKEv1 is unaffected.
Potential Impact
Successful exploitation causes the Libreswan pluto daemon to crash and restart repeatedly, resulting in a denial of service. There is no impact on confidentiality or integrity, and remote code execution is not possible. Systems configured to allow IKEv2 fragmentation are vulnerable, potentially disrupting VPN connectivity or other services relying on the daemon.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, mitigate by configuring Libreswan to disable IKEv2 fragmentation (set fragmentation=no) to prevent triggering the vulnerability. Monitor vendor communications for official patches or updates.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- libreswan
- Date Reserved
- 2026-06-16T15:52:12.674Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a46d9e827e9c79719236155
Added to database: 07/02/2026, 21:36:40 UTC
Last enriched: 07/10/2026, 08:32:23 UTC
Last updated: 08/16/2026, 00:41:10 UTC
Views: 72
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