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

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.

Timeline

Scores

EPSS (exploitation in 30 days)

0.22% · top 87% of all CVEs (15 Nov 2026)

CISA SSVC

Exploitation: none · Automatable: no · Technical impact: partial

The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 4.0.

Affected products

• gnutls

  • affected 3.8.1
  • affected 3.8.2
  • affected 3.8.3
  • affected 3.8.4
  • affected 3.8.5
  • affected 3.8.6
  • affected 3.8.7
  • affected 3.8.8
  • affected 3.8.9
  • affected 3.8.10

• Red Hat · Red Hat Enterprise Linux 10

  • unaffected 0:3.8.10-3.el10_1 – < *

• Red Hat · Red Hat Enterprise Linux 8

  • unaffected 0:3.6.16-8.el8_10.5 – < *

• Red Hat · Red Hat Enterprise Linux 8

  • unaffected 0:3.6.16-8.el8_10.5 – < *

• Red Hat · Red Hat Enterprise Linux 9

  • unaffected 0:3.8.3-10.el9_7 – < *

• Red Hat · Red Hat Enterprise Linux 9

  • unaffected 0:3.8.3-10.el9_7 – < *

• Red Hat · RHEL-8 based Middleware Containers

  • unaffected 7.13.5-4.1777325677 – < *

• Red Hat · RHEL-8 based Middleware Containers

  • unaffected 7.13.5-4.1777325711 – < *

• Red Hat · RHEL-8 based Middleware Containers

  • unaffected 7.13.5-4.1777325710 – < *

• Red Hat · RHEL-8 based Middleware Containers

  • unaffected 7.13.5-3.1777325680 – < *

• Red Hat · RHEL-8 based Middleware Containers

  • unaffected 7.13.5-4.1777325709 – < *

• Red Hat · RHEL-8 based Middleware Containers

  • unaffected 7.13.5-4.1777325680 – < *

• Red Hat · RHEL-8 based Middleware Containers

  • unaffected 7.13.5-4.1777325708 – < *

• Red Hat · Cert Manager support for Red Hat OpenShift release 1.18

  • unaffected 1791459707 – < *

• Red Hat · Cert Manager support for Red Hat OpenShift release 1.18

  • unaffected 1791459711 – < *

• Red Hat · Cert Manager support for Red Hat OpenShift release 1.18

  • unaffected 1791459759 – < *

• Red Hat · Cert Manager support for Red Hat OpenShift release 1.18

  • unaffected 1789029076 – < *

• Red Hat · Cert Manager support for Red Hat OpenShift release 1.18

  • unaffected 1791966259 – < *

• Red Hat · Red Hat Ceph Storage 8

  • unaffected 1774002867 – < *

• Red Hat · Red Hat Discovery 2

  • unaffected 1775668717 – < *

• Red Hat · Red Hat Discovery 2

  • unaffected 1775675922 – < *

• Red Hat · Red Hat Hardened Images

  • unaffected 3.8.12-1.1.hum1 – < *

• Red Hat · Red Hat Insights proxy 1.5

  • unaffected 1773685509 – < *

• Red Hat · Red Hat Update Infrastructure 5

  • unaffected 1773670073 – < *

• Red Hat · Red Hat Update Infrastructure 5

  • unaffected 1773672059 – < *

• Red Hat · Red Hat Update Infrastructure 5

  • unaffected 1773668803 – < *

• Red Hat · Red Hat Update Infrastructure 5

  • unaffected 1773670137 – < *

• Red Hat · Red Hat Enterprise Linux 6

  All versions: affected

• Red Hat · Red Hat Enterprise Linux 7

  All versions: affected

• Red Hat · Red Hat OpenShift Container Platform 4

  All versions: affected

• Red Hat · Red Hat OpenShift Container Platform 4

  All versions: affected

What to do

Workaround: Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability. Applying the upstream patch or vendor-supplied security update is the recommended resolution.

Sources

The same CVE in the primary databases and aggregators, to check against.

• CVE.org record (opens in a new tab)
• CVE List JSON (GitHub) (opens in a new tab)
• NVD (opens in a new tab)
• FIRST EPSS (opens in a new tab)
• EUVD EUVD-2025-206344 (opens in a new tab)
• OSV.dev (opens in a new tab)
• GitHub Advisories (opens in a new tab)
• CIRCL Vulnerability-Lookup (opens in a new tab)

Badge for a README or a ticket

[![CVE-2025-9820](https://cveledger.app/badge/CVE-2025-9820.svg)](https://cveledger.app/cve/CVE-2025-9820)

Record last updated 6 Nov 2026, 17:47 UTC.