CVE-2026-12413Network attack vector

Daemon crash via malformed IKEv2 fragments

Published Jul 2, 2026 · Updated Jul 2, 2026

Denial of service in Libreswan pluto 4.6 through 5.3 allows remote attackers to crash and restart the daemon via malformed IKEv2 fragments. reassemble_v2_incoming_fragments() retains unknown outer payloads in a fixed-size digest array until an off-by-one assertion aborts the process. Exposure requires an IKEv2 connection without fragmentation=no; IKEv1 is unaffected, and the flaw does not enable code execution.

CVSS severity7.5
High
EPSS probability0.60%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Libreswan pluto 4.6 through 5.3 allows remote attackers to crash and restart the daemon via malformed IKEv2 fragments. reassemble_v2_incoming_fragments() retains unknown outer payloads in a fixed-size digest array until an off-by-one assertion aborts the process. Exposure requires an IKEv2 connection without fragmentation=no; IKEv1 is unaffected, and the flaw does not enable code execution.

The record

CVE
CVE-2026-12413
Published
Jul 2, 2026
Updated
Jul 2, 2026
Vendor
The Libreswan Project
Product
Libreswan
Classifications
CWE-617, CWE-193, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 2, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 2, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=4.6 <=5.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Libreswan Project · Libreswanversion=4.6 <=5.3

Published CVSS scores

7.5Libreswan ProjectCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-617Reachable Assertion
CWE-193Off-by-one Error
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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