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Fencer Vulns
high 7.5

CVE-2026-77206 json

IKEv2 pre-authentication Null Pointer Dereference in EAP code

published 2026-10-13 26 d ago modified 2026-10-16 23 d ago also EUVD-2026-100748

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.7%
EPSS 0.7% chance of exploitation in 30 days, percentile 51%
public exploits
0
none known

Summary

Libreswan's IKEv2 state machine has a null pointer dereference bug in the EAP handling code for authentication. As a result of inconsistency within the IKEv2 state machine code, this bug can be triggered by any IKEv2 connection, even if EAP is not configured at all. The error is caused by a fall-through where it incorrectly dereferences ike->sa.st_eap which is NULL. A malicious IKE_AUTH packet can trigger this bug, meaning the peer does not need to be authenticated. The bug results in a crash and restart of the pluto daemon. No remote code execution is possible. Continued exploitation can cause a denial of service.

Patch / fix

  • The Libreswan Project libreswan 5.3.3, 5.4.1
  • libreswan AlmaLinux 9 4.15-11.el9_8
  • libreswan AlmaLinux 8 4.12-2.el8_10.7

almalinux advisories ALSA-2026:89748ALSA-2026:90492

  • libreswan Rocky Linux 8 4.12-2.el8_10.7
  • libreswan Rocky Linux 9 4.15-11.el9_8

rocky linux advisories RLSA-2026:90492RLSA-2026:89748

  • libreswan Alpine 3.24, Alpine 3.23 5.3.3-r0

alpine advisories ALPINE-CVE-2026-77206

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-77206 updated cvss 7.5

libreswan: IKEv2 pre-authentication Null Pointer deref in EAP code

  • Red Hat Fast Datapath for RHEL 9 libreswan Red Hat Enterprise Linux 10 libreswan Red Hat OpenShift Container Platform 4 libreswan Red Hat OpenShift Container Platform 5 openshift/ose-rhel-coreos-9
    affected: workaround, no fix available
  • Red Hat Enterprise Linux AppStream (v. 8) libreswan 4.12-2.el8_10.7
    fixed: vendor fix RHSA-2026:90492
  • Red Hat Enterprise Linux AppStream (v. 9) libreswan 4.15-11.el9_8
    fixed: vendor fix RHSA-2026:89748
  • Red Hat OpenShift Container Platform 4.22 rhcos 4.22.9.8.202611032353
    fixed: vendor fix RHSA-2026:95346
  • Red Hat Enterprise Linux 6 libreswan Red Hat Enterprise Linux 7 libreswan
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
23 d ago

Exploit prediction

0.66% chance of exploitation in the next 30 days, higher than 51% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

  • The Libreswan Project libreswan

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.