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Exploit for Improper Authentication in Openprinting Cups

Sploitus • September 27, 2026

Leaks cupsd's Local auth token, then writes a NOPASSWD sudoers fragment as root via a file:// print queue.

[*] CVE-2026-34990 | user=ctfplayer | cupsd=127.0.0.1:631

[+] ROOT: uid=0(root) gid=0(root) groups=0(root)

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The full story

This article is one source in a clustered incident — the cluster page carries the summary, timeline and every other outlet covering it.

Critical Vulnerability in CUPS Allows Local Privilege Escalation A vulnerability in CUPS (Common UNIX Printing System) version 2.4.16 allows local privilege escalation through improper authentication. Attackers can exploit this flaw by capturing the Local authorization token from the cupsd service, enabling them to execute commands as root. The attack involves setting up a rogue IPP server that challenges cupsd, which responds with its admin token. This token can then be reused to create a malicious print queue that writes to sensitive files, including sudoers configurations. The vulnerability is tracked as CVE-2026-34990, published on April 3, 2026, with the first public proof-of-concept released on August 6, 2026. CUPS versions 2.4.16 and earlier are affected, while version 2.4.17 and later are patched. Security professionals are advised to review their CUPS installations and apply updates promptly. 9 sources 71

Extracted Entities

Exploit for Improper Authentication in Openprinting Cups

The full story

Extracted Entities

Attack Types (1)

CVEs (1)

CWE Weaknesses (1)