--- id: CVE-2025-9820 title: >- A flaw was found in the GnuTLS library, specifically in the gnutls_pkcs11_token_init() function that handles PKCS#11 token initialization 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-… severity: medium cvss: 4 cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L' cwe: - CWE-121 vendor: Red Hat product: Red Hat Enterprise Linux AppStream (v. 8) affected: - enterprise_linux 6 - enterprise_linux 7 - openshift_container_platform 4 - middleware_containers_for_openshift - enterprise_linux_appstream_v_10 - enterprise_linux_appstream_v_8 - enterprise_linux_appstream_v_9 - enterprise_linux_baseos_v_10 - enterprise_linux_baseos_v_8 - enterprise_linux_baseos_v_9 - cert_manager_support_for_red_hat_openshift_release 1.18 - ceph_storage 8 - discovery 2 - hardened_images - insights_proxy 1.5 - update_infrastructure 5 patched: - middleware_containers_for_openshift - enterprise_linux_appstream_v_10 - enterprise_linux_appstream_v_8 - enterprise_linux_appstream_v_9 - enterprise_linux_baseos_v_10 - enterprise_linux_baseos_v_8 - enterprise_linux_baseos_v_9 - cert_manager_support_for_red_hat_openshift_release 1.18 - ceph_storage 8 - discovery 2 - hardened_images - insights_proxy 1.5 - update_infrastructure 5 published: '2026-01-26' updated: '2026-10-14' sourceUpdated: '2026-10-14T20:17:26.560' source: NVD sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2025-9820' references: - url: 'https://access.redhat.com/errata/RHSA-2026:13812' label: secalert@redhat.com - url: 'https://access.redhat.com/errata/RHSA-2026:3477' label: secalert@redhat.com - url: 'https://access.redhat.com/errata/RHSA-2026:4188' label: secalert@redhat.com - url: 'https://access.redhat.com/errata/RHSA-2026:4655' label: secalert@redhat.com - url: 'https://access.redhat.com/errata/RHSA-2026:4943' label: secalert@redhat.com - url: 'https://access.redhat.com/errata/RHSA-2026:5585' label: secalert@redhat.com - url: 'https://access.redhat.com/errata/RHSA-2026:5606' label: secalert@redhat.com - url: 'https://access.redhat.com/errata/RHSA-2026:7329' label: secalert@redhat.com - url: 'https://access.redhat.com/errata/RHSA-2026:7477' label: secalert@redhat.com - url: 'https://access.redhat.com/errata/RHSA-2026:82347' label: secalert@redhat.com - url: 'https://access.redhat.com/errata/RHSA-2026:82354' label: secalert@redhat.com - url: 'https://access.redhat.com/errata/RHSA-2026:82372' label: secalert@redhat.com - url: 'https://access.redhat.com/errata/RHSA-2026:82857' label: secalert@redhat.com - url: 'https://access.redhat.com/security/cve/CVE-2025-9820' label: secalert@redhat.com - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2392528' label: secalert@redhat.com - url: >- https://gitlab.com/gnutls/gnutls/-/commit/1d56f96f6ab5034d677136b9d50b5a75dff0faf5 label: secalert@redhat.com - url: 'https://gitlab.com/gnutls/gnutls/-/issues/1732' label: secalert@redhat.com - url: 'https://www.gnutls.org/security-new.html#GNUTLS-SA-2025-11-18' label: secalert@redhat.com - url: 'http://www.openwall.com/lists/oss-security/2025/11/20/2' label: af854a3a-2127-422b-91ae-364da2661108 - url: 'https://cert-portal.siemens.com/productcert/html/ssa-032379.html' label: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e - url: >- https://security.access.redhat.com/data/csaf/v2/vex/2025/cve-2025-9820.json - url: 'https://www.cve.org/CVERecord?id=CVE-2025-9820' - url: 'https://nvd.nist.gov/vuln/detail/CVE-2025-9820' tags: - nvd - csaf - vex - red-hat - cve.org epss: 0.00222 epssPercentile: 0.1276 ingestedAt: '2026-06-29T13:24:34.636Z' ssvc: exploitation: none automatable: 'no' technicalImpact: partial timestamp: '2026-01-26T20:10:45.615719Z' --- ## Overview 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. ## Remediation Refer to the linked advisories for vendor-supplied fixes and affected version ranges. ## Vendor advisories - **RHSA-2026:13812** · Red Hat · fixed in: Middleware Containers for OpenShift · released 2026-05-05 · [advisory](https://access.redhat.com/errata/RHSA-2026:13812) - **RHSA-2026:3477** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 10), Red Hat Enterprise Linux BaseOS (v. 10) · released 2026-03-02 · [advisory](https://access.redhat.com/errata/RHSA-2026:3477) - **RHSA-2026:5585** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 8), Red Hat Enterprise Linux BaseOS (v. 8) · released 2026-03-24 · [advisory](https://access.redhat.com/errata/RHSA-2026:5585) - **RHSA-2026:4188** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 9), Red Hat Enterprise Linux BaseOS (v. 9) · released 2026-03-10 · [advisory](https://access.redhat.com/errata/RHSA-2026:4188) - **RHSA-2026:82354** · Red Hat · fixed in: Cert Manager support for Red Hat OpenShift release 1.18 · released 2026-10-13 · [advisory](https://access.redhat.com/errata/RHSA-2026:82354) - **RHSA-2026:82372** · Red Hat · fixed in: Cert Manager support for Red Hat OpenShift release 1.18 · released 2026-10-13 · [advisory](https://access.redhat.com/errata/RHSA-2026:82372) - **RHSA-2026:82347** · Red Hat · fixed in: Cert Manager support for Red Hat OpenShift release 1.18 · released 2026-10-13 · [advisory](https://access.redhat.com/errata/RHSA-2026:82347) - **RHSA-2026:5606** · Red Hat · fixed in: Red Hat Ceph Storage 8 · released 2026-03-24 · [advisory](https://access.redhat.com/errata/RHSA-2026:5606) - **RHSA-2026:7329** · Red Hat · fixed in: Red Hat Discovery 2 · released 2026-04-09 · [advisory](https://access.redhat.com/errata/RHSA-2026:7329) - **RHSA-2026:7477** · Red Hat · fixed in: Red Hat Hardened Images · released 2026-04-10 · [advisory](https://access.redhat.com/errata/RHSA-2026:7477) - **RHSA-2026:4655** · Red Hat · fixed in: Red Hat Insights proxy 1.5 · released 2026-03-16 · [advisory](https://access.redhat.com/errata/RHSA-2026:4655) - **Red Hat VEX** · Low · affected: Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Red Hat OpenShift Container Platform 4 · updated 2026-10-14 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2025/cve-2025-9820.json)