CVE-2026-34990: OpenPrinting CUPS Privilege Escalation via Local Admin Token Disclosure

CVE-2026-34990 · Severity: high · CVSS 7.8 · Published 2026-04-03

OpenPrinting CUPS is the standard printing system for Linux and Unix-like operating systems. A vulnerability in how it handles local printer creation allows a standard, unprivileged user to trick the system into granting them administrative access. By exploiting this, an attacker can overwrite critical system files, potentially leading to full control of the computer (root access).

Technologies: OpenPrinting Cups. Vendors: OpenPrinting.

Quick answers

Is CVE-2026-34990 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-34990 being exploited in the wild.
How severe is CVE-2026-34990?
High severity, with a CVSS score of 7.8, published 3 April 2026.
Which products and versions are affected?
OpenPrinting Cups <= 2.4.16.
Is there a fix for CVE-2026-34990?
A patch was published on 2026-04-01: Fixed in version 2.4.17. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-34990 attacked?
It is attacked with local access, in an operating system.
Am I affected by CVE-2026-34990?
Check whether you run OpenPrinting Cups at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

A vulnerability in OpenPrinting CUPS versions 2.4.16 and prior allows a local unprivileged user to coerce the cupsd daemon into authenticating to an attacker-controlled localhost IPP service. This interaction leaks a reusable 'Authorization: Local' token, which the attacker can then use to authorize administrative requests. By combining the 'CUPS-Create-Local-Printer' operation with 'printer-is-shared=true', an attacker can bypass FileDevice policy restrictions to persist a printer queue pointing to a local file (e.g., file:///etc/sudoers.d/pwn). Printing to this queue causes the scheduler to overwrite the target file with attacker-controlled content as the root user. A patch is available in version 2.4.17.

Affected products

  • OpenPrinting CUPS <= 2.4.16

Timeline

  • 2026-04-01: advisory: Vendor advisory GHSA-c54j-2vqw-wpwp published.
  • 2026-04-03: disclosed: CVE-2026-34990 published.
  • 2026-04-01: patched: Fixed in version 2.4.17.

References

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