Debian dla-4787 : ruby-jwt - security update

critical Nessus Plugin ID 348571

Language:

Synopsis

The remote Debian host is missing a security-related update.

Description

The remote Debian 12 host has a package installed that is affected by a vulnerability as referenced in the dla-4787 advisory.

- ------------------------------------------------------------------------- Debian LTS Advisory DLA-4787-1 [email protected] https://www.debian.org/lts/security/ Abhijith PA September 18, 2026 https://wiki.debian.org/LTS
- -------------------------------------------------------------------------

Package : ruby-jwt Version : 2.5.0-1+deb12u1 CVE ID : CVE-2026-45363

ruby-jwt is a Ruby implementation of the RFC 7519 OAuth JSON Web Token standard. JWT.decode(token, '', true, algorithm: 'HS256') accepts an attacker-forged token because OpenSSL::HMAC.digest('SHA256', '', payload) returns a valid digest under an empty key and no empty-key precondition exists in the HMAC algorithm. The same path is reached when a keyfinder block or key_finder: argument returns an empty string, nil, or an array containing nil for an unknown key, affecting HS256, HS384, and HS512 verification through JWT.decode and JWT::EncodedToken#verify_signature!

For Debian 12 bookworm, this problem has been fixed in version 2.5.0-1+deb12u1.

We recommend that you upgrade your ruby-jwt packages.

For the detailed security status of ruby-jwt please refer to its security tracker page at:
https://security-tracker.debian.org/tracker/ruby-jwt

Further information about Debian LTS security advisories, how to apply these updates to your system and frequently asked questions can be found at: https://wiki.debian.org/LTS

Tenable has extracted the preceding description block directly from the Debian security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

Solution

Upgrade the ruby-jwt packages.

Plugin Details

Severity: Critical

ID: 348571

File Name: debian_DLA-4787.nasl

Version: 1.1

Type: Local

Agent: unix

Family: Debian Local Security Checks

Published: 9/21/2026

Updated: 9/21/2026

Supported Sensors: Frictionless Assessment Agent, Nessus Agent, Agentless Assessment, Continuous Assessment, Tenable Cloud Security, Tenable Self-Hosted Container Security, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 4.3

Percentile: 53.46

CVSS v2

Risk Factor: High

Base Score: 9.4

Temporal Score: 7

Vector: CVSS2#AV:N/AC:L/Au:N/C:C/I:C/A:N

CVSS Score Source: CVE-2026-45363

CVSS v3

Risk Factor: Critical

Base Score: 9.1

Temporal Score: 7.9

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

Vulnerability Information

CPE: cpe:/o:debian:debian_linux:12.0, p-cpe:/a:debian:debian_linux:ruby-jwt

Required KB Items: Host/local_checks_enabled, Host/Debian/release, Host/Debian/dpkg-l

Exploit Ease: No known exploits are available

Patch Publication Date: 9/18/2026

Vulnerability Publication Date: 5/18/2026

Reference Information

CVE: CVE-2026-45363

Detections

Analytics