CVE-2025-9820

What it is

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.

At a glance

Exploitability

Can be exploited locally on the machine without logging in. Limited direct impact.

Exploit odds

0.2% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2026-01-26 20:16 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-11-06 18:17 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 0.2% in the next 30 days (EPSS).
• Severity: 4.0 MEDIUM (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2026-01-26 20:16 UTC

Last modified

2026-11-06 18:17 UTC

Exploit probability

0.2% · EPSS, next 30 days

Weakness

CWE-121

Record status

Deferred

Attack profile CVSS 3.1 · 4.0

Attack vector

Local

Complexity

Low

Privileges needed

None

User interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

Low

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2025-9820.md and follow it. Check whether this project is affected by CVE-2025-9820. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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