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Amazon Linux 2023 : cups, cups-client, cups-devel (ALAS2023-2026-1635)

medium Nessus Plugin ID 311327

Synopsis

The remote Amazon Linux 2023 host is missing a security update.

Description

It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2023-2026-1635 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, in a network-exposed cupsd with a shared target queue, an unauthorized client can send a Print-Job to that shared PostScript queue without authentication. The server accepts a page- border value supplied as textWithoutLanguage, preserves an embedded newline through option escaping and reparse, and then reparses the resulting second-line PPD: text as a trusted scheduler control record. A follow-up raw print job can therefore make the server execute an attacker-chosen existing binary such as /usr/bin/vim as lp. At time of publication, there are no publicly available patches. (CVE-2026-34980)

 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)

 OpenPrinting CUPS is an open source printing system for Linux and other Unix-like operating systems. In versions 2.4.16 and prior, an integer underflow vulnerability in _ppdCreateFromIPP() (cups/ppd-cache.c) allows any unprivileged local user to crash the cupsd root process by supplying a negative job-password- supported IPP attribute. The bounds check only caps the upper bound, so a negative value passes validation, is cast to size_t (wrapping to ~2^64), and is used as the length argument to memset() on a 33-byte stack buffer. This causes an immediate SIGSEGV in the cupsd root process. Combined with systemd's Restart=on-failure, an attacker can repeat the crash for sustained denial of service. (CVE-2026-39314)

 OpenPrinting CUPS is an open source printing system for Linux and other Unix-like operating systems. In versions 2.4.16 and prior, a use-after-free vulnerability exists in the CUPS scheduler (cupsd) when temporary printers are automatically deleted. cupsdDeleteTemporaryPrinters() in scheduler/printers.c calls cupsdDeletePrinter() without first expiring subscriptions that reference the printer, leaving cupsd_subscription_t.dest as a dangling pointer to freed heap memory. The dangling pointer is subsequently dereferenced at multiple code sites, causing a crash (denial of service) of the cupsd daemon. With heap grooming, this can be leveraged for code execution. (CVE-2026-39316)

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

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

Solution

Run 'dnf update cups --releasever 2023.11.20260427' or or 'dnf update --advisory ALAS2023-2026-1635 --releasever 2023.11.20260427' to update your system.

See Also

https://alas.aws.amazon.com//AL2023/ALAS2023-2026-1635.html

https://alas.aws.amazon.com/faqs.html

https://explore.alas.aws.amazon.com/CVE-2026-34978.html

https://explore.alas.aws.amazon.com/CVE-2026-34979.html

https://explore.alas.aws.amazon.com/CVE-2026-34980.html

https://explore.alas.aws.amazon.com/CVE-2026-34990.html

https://explore.alas.aws.amazon.com/CVE-2026-39314.html

https://explore.alas.aws.amazon.com/CVE-2026-39316.html

Plugin Details

Severity: Medium

ID: 311327

File Name: al2023_ALAS2023-2026-1635.nasl

Version: 1.1

Type: Local

Agent: unix

Published: 4/30/2026

Updated: 4/30/2026

Supported Sensors: Nessus Agent, Continuous Assessment, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 6.7

CVSS v2

Risk Factor: Medium

Base Score: 6.8

Temporal Score: 5.3

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

CVSS Score Source: CVE-2026-34980

CVSS v3

Risk Factor: High

Base Score: 7.5

Temporal Score: 6.7

Vector: CVSS:3.0/AV:A/AC:H/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: Medium

Base Score: 6.1

Threat Score: 5.6

Threat Vector: CVSS:4.0/E:P

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

Vulnerability Information

CPE: p-cpe:/a:amazon:linux:cups-printerapp, p-cpe:/a:amazon:linux:cups-client-debuginfo, p-cpe:/a:amazon:linux:cups-ipptool-debuginfo, p-cpe:/a:amazon:linux:cups-libs-debuginfo, p-cpe:/a:amazon:linux:cups-libs, p-cpe:/a:amazon:linux:cups-printerapp-debuginfo, p-cpe:/a:amazon:linux:cups-ipptool, p-cpe:/a:amazon:linux:cups-debuginfo, p-cpe:/a:amazon:linux:cups-lpd, cpe:/o:amazon:linux:2023, p-cpe:/a:amazon:linux:cups-lpd-debuginfo, p-cpe:/a:amazon:linux:cups-filesystem, p-cpe:/a:amazon:linux:cups-devel, p-cpe:/a:amazon:linux:cups-client, p-cpe:/a:amazon:linux:cups, p-cpe:/a:amazon:linux:cups-debugsource

Required KB Items: Host/local_checks_enabled, Host/AmazonLinux/release, Host/AmazonLinux/rpm-list

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 4/30/2026

Vulnerability Publication Date: 4/3/2026

Reference Information

CVE: CVE-2026-34978, CVE-2026-34979, CVE-2026-34980, CVE-2026-34990, CVE-2026-39314, CVE-2026-39316