Skip to content
Fencer Vulns
medium 4.0

CVE-2025-9820 json

Gnutls: stack-based buffer overflow in gnutls_pkcs11_token_init() function

published 2026-01-26 9 mo ago modified 2026-11-06 2 d ago also EUVD-2025-206344

cvss
4.0
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 12%
public exploits
0
none known

Summary

A flaw was found in the GnuTLS library, specifically in the gnutls_pkcs11_token_init() function that handles PKCS#11 token initialization. When a token label longer than expected is processed, the function writes past the end of a fixed-size stack buffer. This programming error can cause the application using GnuTLS to crash or, in certain conditions, be exploited for code execution. As a result, systems or applications relying on GnuTLS may be vulnerable to a denial of service or local privilege escalation attacks.

Patch / fix

  • Red Hat Red Hat Enterprise Linux 10 0:3.8.10-3.el10_1
  • Red Hat Red Hat Enterprise Linux 8 0:3.6.16-8.el8_10.5
  • Red Hat Red Hat Enterprise Linux 9 0:3.8.3-10.el9_7
  • Red Hat RHEL-8 based Middleware Containers 7.13.5-3.1777325680, 7.13.5-4.1777325677, 7.13.5-4.1777325680, 7.13.5-4.1777325708, 7.13.5-4.1777325709, 7.13.5-4.1777325710, 7.13.5-4.1777325711
  • Red Hat Cert Manager support for Red Hat OpenShift release 1.18 1789029076, 1791459707, 1791459711, 1791459759, 1791966259
  • Red Hat Red Hat Ceph Storage 8 1774002867
  • Red Hat Red Hat Discovery 2 1775668717, 1775675922
  • Red Hat Red Hat Hardened Images 3.8.12-1.1.hum1
  • Red Hat Red Hat Insights proxy 1.5 1773685509
  • Red Hat Red Hat Update Infrastructure 5 1773668803, 1773670073, 1773670137, 1773672059
  • Siemens SIMATIC CN 4100 V5.0
  • gnutls28 Debian 12 3.7.9-2+deb12u6
  • gnutls28 Debian 13 3.8.9-3+deb13u1
  • gnutls28 Debian 14 3.8.11-3

debian advisories DEBIAN-CVE-2025-9820

  • gnutls28 Ubuntu 22.04 LTS 3.7.3-4ubuntu1.8
  • gnutls28 Ubuntu 24.04 LTS 3.8.3-1.1ubuntu3.5
  • gnutls28 Ubuntu 25.10 3.8.9-3ubuntu2.1
  • gnutls28 Ubuntu Pro 16.04 LTS 3.4.10-4ubuntu1.9+esm3
  • gnutls28 Ubuntu Pro 18.04 LTS 3.5.18-1ubuntu1.6+esm3
  • gnutls28 Ubuntu Pro 20.04 LTS 3.6.13-2ubuntu1.12+esm2
  • gnutls28 Ubuntu Pro FIPS-updates 22.04 LTS 3.7.3-4ubuntu1.8+Fips1.1
  • gnutls28 Ubuntu Pro FIPS-updates 24.04 LTS 3.8.3-1.1ubuntu3.5+Fips1.1

ubuntu advisories UBUNTU-CVE-2025-9820

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

  • gnutls hummingbird 1 3.8.12-1.1.hum1
  • gnutls-c++ hummingbird 1 3.8.12-1.1.hum1
  • gnutls-dane hummingbird 1 3.8.12-1.1.hum1
  • gnutls-fips hummingbird 1 3.8.12-1.1.hum1
  • gnutls-utils hummingbird 1 3.8.12-1.1.hum1
  • mingw32-gnutls hummingbird 1 3.8.12-1.1.hum1
  • mingw64-gnutls hummingbird 1 3.8.12-1.1.hum1
  • gnutls RHEL 8 3.6.16-8.el8_10.5

red hat advisories RHSA-2026:7477RHSA-2026:5585RHSA-2026:4188RHSA-2026:3477

  • gnutls SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 3.8.10-160000.2.1
  • gnutls SLE Micro 5.5, SLE Micro 5.4 3.7.3-150400.4.53.1
  • gnutls Linux Micro 6.1 3.8.3-slfo.1.1_5.1
  • gnutls Linux Micro 6.0 3.8.3-5.1
  • gnutls SLE Module for Basesystem 15 SP7, SLE Module for Basesystem 15 SP6, openSUSE Leap 15.6 3.8.3-150600.4.12.1
  • gnutls SLE Micro 5.2 3.6.7-150200.14.40.1
  • gnutls SLE Micro 5.3 3.7.3-150400.19.1
  • gnutls SLES LTSS Extended Security 12 SP5, SLES 12 SP5-LTSS 3.3.27-3.18.1

suse advisories SUSE-SU-2026:2367-1SUSE-SU-2026:20962-1SUSE-SU-2026:20968-1SUSE-SU-2026:20984-1SUSE-SU-2025:4525-1SUSE-SU-2025:21222-1

  • gnutls openSUSE Leap 16.0 3.8.10-160000.2.1
  • gnutls openSUSE Tumbleweed 3.8.11-1.1

opensuse advisories openSUSE-SU-2026:20446-1openSUSE-SU-2025:15765-1

  • gnutls AlmaLinux 8 3.6.16-8.el8_10.5
  • gnutls-c++ AlmaLinux 8 3.6.16-8.el8_10.5
  • gnutls-dane AlmaLinux 8 3.6.16-8.el8_10.5
  • gnutls-utils AlmaLinux 8 3.6.16-8.el8_10.5
  • gnutls AlmaLinux 9 3.8.3-10.el9_7
  • gnutls-c++ AlmaLinux 9 3.8.3-10.el9_7
  • gnutls-dane AlmaLinux 9 3.8.3-10.el9_7
  • gnutls-utils AlmaLinux 9 3.8.3-10.el9_7

almalinux advisories ALSA-2026:5585ALSA-2026:4188ALSA-2026:3477

  • gnutls Rocky Linux 8 3.6.16-8.el8_10.5
  • gnutls Rocky Linux 9 3.8.3-10.el9_7
  • gnutls Rocky Linux 10 3.8.10-3.el10_1

rocky linux advisories RLSA-2026:5585RLSA-2026:4188RLSA-2026:3477

  • gnutls Alpine 3.22, Alpine 3.21, Alpine 3.20 3.8.12-r0
  • gnutls Alpine 3.24, Alpine 3.23 3.8.11-r0

alpine advisories ALPINE-CVE-2025-9820

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

  • gnutls CBL-Mariner 2.0 3.7.11-6
  • gnutls Azure Linux 3.0 3.8.3-8

azure linux advisories AZL-75258AZL-75261

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-2025-9820 updated cvss 4.0

gnutls: Stack-based Buffer Overflow in gnutls_pkcs11_token_init() Function

  • Red Hat Enterprise Linux 6 gnutls, gnutls-guile, gnutls-utils Red Hat Enterprise Linux 7 gnutls, gnutls-c++, gnutls-dane, gnutls-utils Red Hat OpenShift Container Platform 4 openshift/ose-rhel-coreos-8, openshift/ose-rhel-coreos-9
    affected: workaround, no fix available “Fix deferred”
  • Red Hat Cert Manager support for Red Hat OpenShift release 1.18 cert-manager/cert-manager-operator-rhel9 1789029076, cert-manager/jetstack-cert-manager-rhel9 1791459711, cert-manager/cert-manager-istio-csr-rhel9 1791459759, cert-manager/cert-manager-operator-bundle 1791966259, cert-manager/jetstack-cert-manager-acmesolver-rhel9 1791459707
    fixed: vendor fix RHSA-2026:82354
  • Red Hat Middleware Containers for OpenShift rhpam-7/rhpam-kieserver-rhel8 7.13.5-4.1777325709, rhpam-7/rhpam-controller-rhel8 7.13.5-4.1777325710, rhpam-7/rhpam-dashbuilder-rhel8 7.13.5-3.1777325680, rhpam-7/rhpam-smartrouter-rhel8 7.13.5-4.1777325708, rhpam-7/rhpam-businesscentral-rhel8 7.13.5-4.1777325711, rhpam-7/rhpam-process-migration-rhel8 7.13.5-4.1777325680, +1 more
    fixed: vendor fix RHSA-2026:13812
  • Red Hat Ceph Storage 8 rhceph 1774002867
    fixed: vendor fix RHSA-2026:5606
  • Red Hat Discovery 2 discovery 1775668717, discovery 1775675922
    fixed: vendor fix RHSA-2026:7329
  • Red Hat Enterprise Linux AppStream (v. 8) gnutls-c++ 3.6.16-8.el8_10.5, gnutls-dane 3.6.16-8.el8_10.5, gnutls-utils 3.6.16-8.el8_10.5
    fixed: vendor fix RHSA-2026:5585
  • Red Hat Enterprise Linux AppStream (v. 9) gnutls-c++ 3.8.3-10.el9_7, gnutls-dane 3.8.3-10.el9_7, gnutls-utils 3.8.3-10.el9_7
    fixed: vendor fix RHSA-2026:4188
  • Red Hat Enterprise Linux AppStream (v. 10) gnutls-c++ 3.8.10-3.el10_1, gnutls-dane 3.8.10-3.el10_1, gnutls-fips 3.8.10-3.el10_1, gnutls-utils 3.8.10-3.el10_1
    fixed: vendor fix RHSA-2026:3477
show 7 more
  • Red Hat Enterprise Linux BaseOS (v. 8) gnutls 3.6.16-8.el8_10.5
    fixed: vendor fix RHSA-2026:5585
  • Red Hat Enterprise Linux BaseOS (v. 9) gnutls 3.8.3-10.el9_7
    fixed: vendor fix RHSA-2026:4188
  • Red Hat Enterprise Linux BaseOS (v. 10) gnutls 3.8.10-3.el10_1
    fixed: vendor fix RHSA-2026:3477
  • Red Hat Hardened Images gnutls 3.8.12-1.1.hum1, gnutls-c++ 3.8.12-1.1.hum1, gnutls-dane 3.8.12-1.1.hum1, gnutls-fips 3.8.12-1.1.hum1, gnutls-utils 3.8.12-1.1.hum1, mingw32-gnutls 3.8.12-1.1.hum1, +1 more
    fixed: vendor fix RHSA-2026:7477
  • Red Hat Insights proxy 1.5 insights-proxy 1773685509
    fixed: vendor fix RHSA-2026:4655
  • Red Hat Update Infrastructure 5 rhui5 1773668803, rhui5 1773670073, rhui5 1773670137, rhui5 1773672059
    fixed: vendor fix RHSA-2026:4943
  • Red Hat Middleware Containers for OpenShift rhpam-7/rhpam-operator-bundle 7.13.5-40
    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
partial
Assessed
9 mo ago

Exploit prediction

0.22% chance of exploitation in the next 30 days, higher than 12% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 4.0 CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Affected products

  • Red Hat Red Hat Enterprise Linux 10
  • Red Hat Red Hat Enterprise Linux 8
  • Red Hat Red Hat Enterprise Linux 9
  • Red Hat RHEL-8 based Middleware Containers
  • Red Hat Cert Manager support for Red Hat OpenShift release 1.18
  • Red Hat Red Hat Ceph Storage 8
  • Red Hat Red Hat Discovery 2
  • Red Hat Red Hat Hardened Images
  • Red Hat Red Hat Insights proxy 1.5
  • Red Hat Red Hat Update Infrastructure 5
  • Red Hat Red Hat Enterprise Linux 6
  • Red Hat Red Hat Enterprise Linux 7
  • Red Hat Red Hat OpenShift Container Platform 4
  • Siemens SIMATIC CN 4100

Classification

Weakness
  • CWE-121 Stack-based Buffer Overflow

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.