AlmaLinux 9.6 [TuxCare] Security Update: cups / cups-client / cups-devel / cups-filesystem / cups-ipptool / etc Multiple Vulnerabilities (ALMALINUX9.6:CLSA-2026:1785836378)

medium Nessus Plugin ID 351570

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Synopsis

The AlmaLinux host is missing one or more security updates.

Description

The AlmaLinux 9.6 host has packages installed that are affected by multiple vulnerabilities as referenced in the TuxCare ALMALINUX9.6:CLSA-2026:1785836378 advisory.

- OpenPrinting CUPS is an open source printing system for Linux and other Unix-like operating systems. In versions 2.4.16 and prior, the RSS notifier allows .. path traversal in notify-recipient-uri (e.g., rss:///../job.cache), letting a remote IPP client write RSS XML bytes outside CacheDir/rss (anywhere that is lp-writable). In particular, because CacheDir is group-writable by default (typically root:lp and mode 0770), the notifier (running as lp) can replace root-managed state files via temp-file + rename(). This PoC clobbers CacheDir/job.cache with RSS XML, and after restarting cupsd the scheduler fails to parse the job cache and previously queued jobs disappear. At time of publication, there are no publicly available patches. (CVE-2026-34978)

- OpenPrinting CUPS is an open source printing system for Linux and other Unix-like operating systems. In versions 2.4.16 and prior, there is a heap-based buffer overflow in the CUPS scheduler when building filter option strings from job attribute. At time of publication, there are no publicly available patches.
(CVE-2026-34979)

- OpenPrinting CUPS is an open source printing system for Linux and other Unix-like operating systems. In versions 2.4.16 and prior, a local unprivileged user can coerce cupsd into authenticating to an attacker- controlled localhost IPP service with a reusable Authorization: Local ... token. That token is enough to drive /admin/ requests on localhost, and the attacker can combine CUPS-Create-Local-Printer with printer- is-shared=true to persist a file:///... queue even though the normal FileDevice policy rejects such URIs.
Printing to that queue gives an arbitrary root file overwrite; the PoC below uses that primitive to drop a sudoers fragment and demonstrate root command execution. At time of publication, there are no publicly available patches. (CVE-2026-34990)

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

Solution

Update the affected packages based on the guidance in TuxCare advisory ALMALINUX9.6:CLSA-2026:1785836378.

Plugin Details

Severity: Medium

ID: 351570

File Name: tuxcare_alma_linux_9.6_CLSA-2026-1785836378.nasl

Version: 1.1

Type: Local

Family: Alma Linux Local Security Checks

Published: 9/30/2026

Updated: 9/30/2026

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

Risk Information

VPR

Risk Factor: High

Score: 7.9

Percentile: 99.35

Vendor

Vendor Severity: Moderate

CVSS v2

Risk Factor: Medium

Base Score: 6.8

Temporal Score: 5.6

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

CVSS Score Source: CVE-2026-34990

CVSS v3

Risk Factor: High

Base Score: 7.8

Temporal Score: 7.2

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

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

CVSS v4

Risk Factor: Medium

Base Score: 5

Threat Score: 2.3

Threat Vector: CVSS:4.0/E:P

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

Vulnerability Information

Required KB Items: Host/local_checks_enabled, Host/cpu, Host/AlmaLinux/release, Host/AlmaLinux/rpm-list, Host/OS/extended-third-party

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 8/4/2026

Vulnerability Publication Date: 4/3/2026

Reference Information

CVE: CVE-2026-34978, CVE-2026-34979, CVE-2026-34990

CLSA: 2026:1785836378

Detections

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