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Fencer Vulns
high 8.1

CVE-2025-62291 json

In the eap-mschapv2 plugin (client-side) in strongSwan before 6.0.3, a malicious EAP-MSCHAPv2 server can send a crafted message of size 6 t…

published 2026-01-16 9 mo ago modified 2026-06-17 4 mo ago also EUVD-2026-2870

cvss
8.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.0%
EPSS 1.0% chance of exploitation in 30 days, percentile 62%
public exploits
0
none known

Summary

In the eap-mschapv2 plugin (client-side) in strongSwan before 6.0.3, a malicious EAP-MSCHAPv2 server can send a crafted message of size 6 through 8, and cause an integer underflow that potentially results in a heap-based buffer overflow.

Patch / fix

  • strongSwan strongSwan 6.0.3
  • strongswan Debian 12 5.9.8-5+deb12u2
  • strongswan Debian 13 6.0.1-6+deb13u2
  • strongswan Debian 14 6.0.3-1

debian advisories DEBIAN-CVE-2025-62291

  • strongswan Ubuntu 22.04 LTS 5.9.5-2ubuntu2.4
  • strongswan Ubuntu 24.04 LTS 5.9.13-2ubuntu4.24.04.1
  • strongswan Ubuntu 25.10 6.0.1-6ubuntu4.1
  • strongswan Ubuntu 26.04 LTS 6.0.1-6ubuntu5
  • strongswan Ubuntu Pro FIPS-updates 22.04 LTS 5.9.5-2ubuntu2.4+Fips1

ubuntu advisories UBUNTU-CVE-2025-62291

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • strongswan SLES for SAP applications 16.0, SLES 16.0 6.0.1-160000.3.1
  • strongswan SLES for SAP 15 SP5, SLES 15 SP5-LTSS, SLE High Performance Computing 15 SP5-LTSS +1 more 5.9.11-150500.5.9.1
  • strongswan SLES for SAP 15 SP3, SLES 15 SP3-LTSS, SLE High Performance Computing 15 SP3-LTSS +1 more 5.8.2-150200.11.45.1
  • strongswan SLES for SAP 15 SP4, SLES 15 SP4-LTSS, SLE High Performance Computing 15 SP4-LTSS +3 more 5.9.11-150400.19.20.1
  • strongswan SLE Workstation Extension 15 SP6, SLE Module for Package Hub 15 SP6, SLE Module for Basesystem 15 SP6 +1 more 5.9.12-150600.3.5.2
  • strongswan SLE Workstation Extension 15 SP7, SLE Module for Package Hub 15 SP7, SLE Module for Basesystem 15 SP7 5.9.14-150700.3.3.1
  • strongswan SLES LTSS Extended Security 12 SP5, SLES 12 SP5-LTSS 5.1.3-26.29.1

suse advisories SUSE-SU-2025:21167-1SUSE-SU-2025:3904-1SUSE-SU-2025:3873-1SUSE-SU-2025:3857-1SUSE-SU-2025:3856-1SUSE-SU-2025:3855-1

  • strongswan openSUSE Leap 16.0 6.0.1-160000.3.1
  • strongswan openSUSE Tumbleweed 6.0.3-1.1

opensuse advisories openSUSE-SU-2025:20132-1openSUSE-SU-2025:15681-1

  • strongswan Alpine 3.20 5.9.13-r2
  • strongswan Alpine 3.22, Alpine 3.21 5.9.14-r1
  • strongswan Alpine 3.24, Alpine 3.23 5.9.14-r3

alpine advisories ALPINE-CVE-2025-62291

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

  • strongswan Azure Linux 3.0 5.9.14-8
  • strongswan CBL-Mariner 2.0 5.9.10-4

azure linux advisories AZL-74660AZL-74766

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

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-2025-62291 updated cvss 8.1

strongswan: strongSwan: Arbitrary Code Execution and Denial of Service via crafted EAP-MSCHAPv2 message

  • Red Hat All currently supported Red Hat products
    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
no
Technical impact
total
Assessed
9 mo ago

Exploit prediction

0.98% chance of exploitation in the next 30 days, higher than 62% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 8.1 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

  • strongSwan strongSwan

Classification

Weakness
  • CWE-191 Integer Underflow (Wrap or Wraparound)

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.