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Vulnerability · Published Jan 26, 2026 · Assigned by redhat

CVE-2025-9820Gnutls: stack-based buffer overflow in gnutls_pkcs11_token_init() function

Medium 4.0

In plain English

A medium-severity stack buffer overflow in gnutls. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 13% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)4.0Medium
Exploit odds (30 days)0.2%top 87.1% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

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.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
AlmaLinux:10gnutls3.8.10-3.el10_1ALSA-2026:3477
AlmaLinux:8gnutls3.6.16-8.el8_10.5ALSA-2026:5585
AlmaLinux:9gnutls3.8.3-10.el9_7ALSA-2026:4188
AlmaLinux:10gnutls-c++3.8.10-3.el10_1ALSA-2026:3477
AlmaLinux:8gnutls-c++3.6.16-8.el8_10.5ALSA-2026:5585
AlmaLinux:9gnutls-c++3.8.3-10.el9_7ALSA-2026:4188
AlmaLinux:10gnutls-dane3.8.10-3.el10_1ALSA-2026:3477
AlmaLinux:8gnutls-dane3.6.16-8.el8_10.5ALSA-2026:5585
AlmaLinux:9gnutls-dane3.8.3-10.el9_7ALSA-2026:4188
AlmaLinux:10gnutls-devel3.8.10-3.el10_1ALSA-2026:3477
AlmaLinux:8gnutls-devel3.6.16-8.el8_10.5ALSA-2026:5585
AlmaLinux:9gnutls-devel3.8.3-10.el9_7ALSA-2026:4188
AlmaLinux:10gnutls-fips3.8.10-3.el10_1ALSA-2026:3477
AlmaLinux:10gnutls-utils3.8.10-3.el10_1ALSA-2026:3477
AlmaLinux:8gnutls-utils3.6.16-8.el8_10.5ALSA-2026:5585
AlmaLinux:9gnutls-utils3.8.3-10.el9_7ALSA-2026:4188
Alpine:v3.20gnutls3.8.12-r0ALPINE-CVE-2025-9820
Alpine:v3.21gnutls3.8.12-r0ALPINE-CVE-2025-9820
Alpine:v3.22gnutls3.8.12-r0ALPINE-CVE-2025-9820
Alpine:v3.23gnutls3.8.11-r0ALPINE-CVE-2025-9820
Alpine:v3.24gnutls3.8.11-r0ALPINE-CVE-2025-9820
Debian:12gnutls283.7.9-2+deb12u6DEBIAN-CVE-2025-9820
Debian:13gnutls283.8.9-3+deb13u1DEBIAN-CVE-2025-9820
Debian:14gnutls283.8.11-3DEBIAN-CVE-2025-9820
Rocky Linux:10gnutls0:3.8.10-3.el10_1RLSA-2026:3477
Rocky Linux:8gnutls0:3.6.16-8.el8_10.5RLSA-2026:5585
Rocky Linux:9gnutls0:3.8.3-10.el9_7RLSA-2026:4188
Ubuntu:22.04:LTSgnutls283.7.3-4ubuntu1.8USN-8043-1
Ubuntu:22.04:LTSgnutls283.7.3-4ubuntu1.8UBUNTU-CVE-2025-9820
Ubuntu:24.04:LTSgnutls283.8.3-1.1ubuntu3.5UBUNTU-CVE-2025-9820
Ubuntu:24.04:LTSgnutls283.8.3-1.1ubuntu3.5USN-8043-1
Ubuntu:25.10gnutls283.8.9-3ubuntu2.1UBUNTU-CVE-2025-9820
Ubuntu:25.10gnutls283.8.9-3ubuntu2.1USN-8043-1

Affected products (as reported)

VendorProductVersions
gnutls 3.8.13.8.23.8.33.8.43.8.53.8.63.8.73.8.8
Red Hat Red Hat Enterprise Linux 10 see references
Red Hat Red Hat Enterprise Linux 8 see references
Red Hat Red Hat Enterprise Linux 8 see references
Red Hat Red Hat Enterprise Linux 9 see references
Red Hat Red Hat Enterprise Linux 9 see references
Red Hat RHEL-8 based Middleware Containers see references
Red Hat RHEL-8 based Middleware Containers see references
Red Hat RHEL-8 based Middleware Containers see references
Red Hat RHEL-8 based Middleware Containers see references
Red Hat RHEL-8 based Middleware Containers see references
Red Hat RHEL-8 based Middleware Containers see references
Red Hat RHEL-8 based Middleware Containers see references
Red Hat Cert Manager support for Red Hat OpenShift release 1.18 see references
Red Hat Cert Manager support for Red Hat OpenShift release 1.18 see references
Red Hat Cert Manager support for Red Hat OpenShift release 1.18 see references
Red Hat Cert Manager support for Red Hat OpenShift release 1.18 see references
Red Hat Cert Manager support for Red Hat OpenShift release 1.18 see references
Red Hat Red Hat Ceph Storage 8 see references
Red Hat Red Hat Discovery 2 see references
Red Hat Red Hat Discovery 2 see references
Red Hat Red Hat Hardened Images see references
Red Hat Red Hat Insights proxy 1.5 see references
Red Hat Red Hat Update Infrastructure 5 see references
Red Hat Red Hat Update Infrastructure 5 see references
Red Hat Red Hat Update Infrastructure 5 see references
Red Hat Red Hat Update Infrastructure 5 see references
Red Hat Red Hat Enterprise Linux 6 see references
Red Hat Red Hat Enterprise Linux 7 see references
Red Hat Red Hat OpenShift Container Platform 4 see references

Weakness: CWE-121 · Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

References