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Ubuntu 25.10 : Rack::Session vulnerability (USN-8190-1)

critical Nessus Plugin ID 307893

Synopsis

The remote Ubuntu host is missing a security update.

Description

The remote Ubuntu 25.10 host has a package installed that is affected by a vulnerability as referenced in the USN-8190-1 advisory.

 SeungMyung Lee discovered that Rack::Session did not properly reject cookies upon decryption failure. A remote attacker could use this issue to manipulate session contents and possibly gain unauthorized access.

Tenable has extracted the preceding description block directly from the Ubuntu 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

Update the affected ruby-rack-session package.

See Also

https://ubuntu.com/security/notices/USN-8190-1

Plugin Details

Severity: Critical

ID: 307893

File Name: ubuntu_USN-8190-1.nasl

Version: 1.1

Type: Local

Agent: unix

Published: 4/21/2026

Updated: 4/21/2026

Supported Sensors: Continuous Assessment, Nessus Agent, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 6.7

CVSS v2

Risk Factor: Critical

Base Score: 10

Temporal Score: 7.8

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

CVSS Score Source: CVE-2026-39324

CVSS v3

Risk Factor: Critical

Base Score: 9.8

Temporal Score: 8.8

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

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

CVSS v4

Risk Factor: Critical

Base Score: 9.3

Threat Score: 8.9

Threat Vector: CVSS:4.0/E:P

Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Vulnerability Information

CPE: cpe:/o:canonical:ubuntu_linux:25.10, p-cpe:/a:canonical:ubuntu_linux:ruby-rack-session

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

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 4/20/2026

Vulnerability Publication Date: 4/7/2026

Reference Information

CVE: CVE-2026-39324

USN: 8190-1