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Fencer Vulns
high 7.5

CVE-2026-25075 json

strongSwan 4.5.0 < 6.0.5 EAP-TTLS AVP Parsing Integer Underflow

published 2026-03-23 7 mo ago modified 2026-07-14 3 mo ago also EUVD-2026-14477

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.1%
EPSS 1.1% chance of exploitation in 30 days, percentile 64%
public exploits
0
none known

Summary

strongSwan versions 4.5.0 prior to 6.0.5 contain an integer underflow vulnerability in the EAP-TTLS AVP parser that allows unauthenticated remote attackers to cause a denial of service by sending crafted AVP data with invalid length fields during IKEv2 authentication. Attackers can exploit the failure to validate AVP length fields before subtraction to trigger excessive memory allocation or NULL pointer dereference, crashing the charon IKE daemon.

Patch / fix

  • strongSwan strongSwan 6.0.5
  • strongswan Debian 12 5.9.8-5+deb12u3
  • strongswan Debian 13 6.0.1-6+deb13u4
  • strongswan Debian 14 6.0.5-1

debian advisories DEBIAN-CVE-2026-25075

  • strongswan Ubuntu 22.04 LTS 5.9.5-2ubuntu2.5
  • strongswan Ubuntu 24.04 LTS 5.9.13-2ubuntu4.24.04.2
  • strongswan Ubuntu 25.10 6.0.1-6ubuntu4.2
  • strongswan Ubuntu Pro FIPS-updates 22.04 LTS 5.9.5-2ubuntu2.5+Fips1

ubuntu advisories UBUNTU-CVE-2026-25075

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 6.0.4-160000.1.1
  • strongswan SLES for SAP 15 SP4, SLES 15 SP4-LTSS, SLE High Performance Computing 15 SP4-LTSS +1 more 5.9.11-150400.19.26.1
  • strongswan SLE Workstation Extension 15 SP7, SLE Module for Package Hub 15 SP7, SLE Module for Basesystem 15 SP7 5.9.14-150700.3.9.1
  • strongswan SLES for SAP 15 SP6, SLES 15 SP6-LTSS, openSUSE Leap 15.6 5.9.12-150600.3.11.1
  • strongswan SLES for SAP 15 SP5, SLES 15 SP5-LTSS, SLE High Performance Computing 15 SP5-LTSS +1 more 5.9.11-150500.5.14.1
  • strongswan SLES LTSS Extended Security 12 SP5, SLES 12 SP5-LTSS 5.1.3-26.32.1

suse advisories SUSE-SU-2026:21203-1SUSE-SU-2026:1307-1SUSE-SU-2026:0981-1SUSE-SU-2026:0980-1SUSE-SU-2026:0979-1SUSE-SU-2026:0978-1

  • strongswan openSUSE Leap 16.0 6.0.4-160000.1.1
  • strongswan openSUSE Tumbleweed 6.0.5-1.1

opensuse advisories openSUSE-SU-2026:20547-1openSUSE-SU-2026:10441-1

  • strongswan Azure Linux 3.0 5.9.14-9

azure linux advisories AZL-80300

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-2026-25075 updated cvss 7.5

strongSwan: strongSwan: Denial of Service via integer underflow in EAP-TTLS AVP parser

  • 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
yes
Technical impact
partial
Assessed
7 mo ago

Exploit prediction

1.05% chance of exploitation in the next 30 days, higher than 64% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • strongswan.org https://www.strongswan.org/blog/2026/03/23/strongswan-vulnerability-(cve-2026-25075).html referenced PoC, tagged "exploit" by a source, unverified
  • y637f9qq2x.com https://y637f9qq2x.com/posts/cve-2026-25075/ referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 4.0 8.7 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CNA 4.0 8.7 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected products

  • strongSwan strongSwan

Classification

Weakness
  • CWE-191 Integer Underflow (Wrap or Wraparound)
  • CWE-476 NULL Pointer Dereference

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.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.