CVE-2026-34978
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).
Does this matter?
Lower severity and a low EPSS score (0.41%). Track it; it rarely justifies an emergency change on its own.
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.
- CVSS 3.1
- 6.5 MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L
- EPSS
- 0.41% probability · 34th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-22
- Affected
- openprinting/cups
- Source
- security-advisories@github.com
References
- https://github.com/OpenPrinting/cups/security/advisories/GHSA-f53q-7mxp-9gcrExploit, Vendor Advisory
- https://github.com/OpenPrinting/cups/security/advisories/GHSA-f53q-7mxp-9gcrExploit, Vendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.