CVE-2026-34978
Publication date 3 April 2026
Last updated 8 June 2026
Ubuntu priority
Description
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.
Status
| Package | Ubuntu Release | Status |
|---|---|---|
| cups | 26.04 LTS resolute |
Fixed 2.4.16-1ubuntu1.2
|
| 25.10 questing |
Fixed 2.4.12-0ubuntu3.9
|
|
| 24.04 LTS noble |
Fixed 2.4.7-1.2ubuntu7.13
|
|
| 22.04 LTS jammy |
Fixed 2.4.1op1-1ubuntu4.20
|
|
| 20.04 LTS focal |
Needs evaluation
|
|
| 18.04 LTS bionic |
Needs evaluation
|
|
| 16.04 LTS xenial |
Needs evaluation
|
Severity score breakdown
CVSS version: CVSS v3.0
Base score
6.5 · Medium
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L
References
Related Ubuntu Security Notices (USN)
- USN-8405-1
- CUPS vulnerabilities
- 8 June 2026