OpenPrinting CUPS up to 2.4.16 on Linux rename path traversal

Summaryinfo

A vulnerability, which was classified as critical, was found in OpenPrinting CUPS up to 2.4.16 on Linux. This impacts the function rename. Executing a manipulation can lead to path traversal. This vulnerability is registered as CVE-2026-34978. It is possible to launch the attack remotely. No exploit is available.

Detailsinfo

A vulnerability was found in OpenPrinting CUPS up to 2.4.16 on Linux. It has been declared as critical. This vulnerability affects the function rename. The manipulation with an unknown input leads to a path traversal vulnerability. The CWE definition for the vulnerability is CWE-22. The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory. As an impact it is known to affect integrity, and availability. CVE summarizes:

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.

The advisory is available at github.com. This vulnerability was named CVE-2026-34978 since 03/31/2026. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. Technical details are known, but there is no available exploit. The structure of the vulnerability defines a possible price range of USD $0-$5k at the moment (estimation calculated on 07/21/2026). This vulnerability is assigned to T1006 by the MITRE ATT&CK project.

The vulnerability scanner Nessus provides a plugin with the ID 307661 (Fedora 43 : cups (2026-82a2214b53)), which helps to determine the existence of the flaw in a target environment.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

The vulnerability is also documented in the databases at Tenable (307661) and CERT Bund (WID-SEC-2026-0947). If you want to get best quality of vulnerability data, you may have to visit VulDB.

Affected

• Amazon Linux 2
• Fedora Linux
• Ubuntu Linux
• SUSE Linux
• SUSE openSUSE
• Microsoft Azure Linux
• Open Source CUPS

Productinfo

Type

• Printing Software

Vendor

• OpenPrinting

Name

• CUPS

Version

• 2.4.0
• 2.4.1
• 2.4.2
• 2.4.3
• 2.4.4
• 2.4.5
• 2.4.6
• 2.4.7
• 2.4.8
• 2.4.9
• 2.4.10
• 2.4.11
• 2.4.12
• 2.4.13
• 2.4.14
• 2.4.15
• 2.4.16

Website

• Product: https://github.com/OpenPrinting/cups/

CPE 2.3info

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CPE 2.2info

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Entryinfo

If you want to get best quality of vulnerability data, you may have to visit VulDB.

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