CVE-2025-9820
This programming error can cause the application using GnuTLS to crash or, in certain conditions, be exploited for code execution.
Does this matter?
Lower severity and a low EPSS score (0.21%). Track it; it rarely justifies an emergency change on its own.
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.
- CVSS 3.1
- 4.0 MEDIUMCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
- EPSS
- 0.21% probability · 11th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-121
- Source
- secalert@redhat.com
References
- https://access.redhat.com/errata/RHSA-2026:13812
- https://access.redhat.com/errata/RHSA-2026:3477
- https://access.redhat.com/errata/RHSA-2026:4188
- https://access.redhat.com/errata/RHSA-2026:4655
- https://access.redhat.com/errata/RHSA-2026:4943
- https://access.redhat.com/errata/RHSA-2026:5585
- https://access.redhat.com/errata/RHSA-2026:5606
- https://access.redhat.com/errata/RHSA-2026:7329
- https://access.redhat.com/errata/RHSA-2026:7477
- https://access.redhat.com/security/cve/CVE-2025-9820
- https://bugzilla.redhat.com/show_bug.cgi?id=2392528
- https://gitlab.com/gnutls/gnutls/-/commit/1d56f96f6ab5034d677136b9d50b5a75dff0faf5
- https://gitlab.com/gnutls/gnutls/-/issues/1732
- https://www.gnutls.org/security-new.html#GNUTLS-SA-2025-11-18
- http://www.openwall.com/lists/oss-security/2025/11/20/2
- https://cert-portal.siemens.com/productcert/html/ssa-032379.html
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.