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

CVE-2026-34978 is fixed in 26 products on 1 platform, first by DEBIAN-CVE-2026-34978, released April 3, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-34978
- Priority: Routine
- CVSS: 6.5 (Moderate)
- EPSS: 0.0042
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Apr 3, 2026
- Weakness: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-34978

## 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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | cups Debian 14 | 2.4.17-1 | [DEBIAN-CVE-2026-34978](https://patchblox.com/security/data/fix/linux/debian-cve-2026-34978.md) | Apr 3, 2026 |
| Linux | cups Ubuntu 22.04.1 LTS (jammy) | 2.4.1op1-1ubuntu4.20 | [cups 2.4.1op1-1ubuntu4.20](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-cups-2.4.1op1-1ubuntu4.20.md) | Apr 24, 2026 |
| Linux | cups Ubuntu 24.04.5 LTS (noble) | 2.4.7-1.2ubuntu7.13 | [cups 2.4.7-1.2ubuntu7.13](https://patchblox.com/security/data/fix/linux/ubuntu-noble-cups-2.4.7-1.2ubuntu7.13.md) | Apr 24, 2026 |
| Linux | cups Ubuntu 25.10 (questing) | 2.4.12-0ubuntu3.9 | [cups 2.4.12-0ubuntu3.9](https://patchblox.com/security/data/fix/linux/ubuntu-questing-cups-2.4.12-0ubuntu3.9.md) | Apr 24, 2026 |
| Linux | cups Ubuntu 26.04.1 LTS (resolute) | 2.4.16-1ubuntu1.2 | [cups 2.4.16-1ubuntu1.2](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-cups-2.4.16-1ubuntu1.2.md) | Apr 24, 2026 |
| Linux | cups amzn 2023 | 1:2.4.16-1.amzn2023.0.3 | [ALAS2023-2026-1635](https://patchblox.com/security/data/fix/linux/alas2023-2026-1635.md) | Apr 27, 2026 |
| Linux | cups sles 15.7 | 2.2.7-150000.3.93.1 | [SUSE-SU-2026:2732-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-2732-1.md) | Jul 2, 2026 |
| Linux | cups-bsd Ubuntu 22.04.1 LTS (jammy) | 2.4.1op1-1ubuntu4.20 | [cups-bsd 2.4.1op1-1ubuntu4.20](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-cups-bsd-2.4.1op1-1ubuntu4.20.md) | Apr 24, 2026 |
| Linux | cups-bsd Ubuntu 24.04.5 LTS (noble) | 2.4.7-1.2ubuntu7.13 | [cups-bsd 2.4.7-1.2ubuntu7.13](https://patchblox.com/security/data/fix/linux/ubuntu-noble-cups-bsd-2.4.7-1.2ubuntu7.13.md) | Apr 24, 2026 |
| Linux | cups-bsd Ubuntu 25.10 (questing) | 2.4.12-0ubuntu3.9 | [cups-bsd 2.4.12-0ubuntu3.9](https://patchblox.com/security/data/fix/linux/ubuntu-questing-cups-bsd-2.4.12-0ubuntu3.9.md) | Apr 24, 2026 |
| Linux | cups-bsd Ubuntu 26.04.1 LTS (resolute) | 2.4.16-1ubuntu1.2 | [cups-bsd 2.4.16-1ubuntu1.2](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-cups-bsd-2.4.16-1ubuntu1.2.md) | Apr 24, 2026 |
| Linux | cups-client Ubuntu 22.04.1 LTS (jammy) | 2.4.1op1-1ubuntu4.20 | [cups-client 2.4.1op1-1ubuntu4.20](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-cups-client-2.4.1op1-1ubuntu4.20.md) | Apr 24, 2026 |
| Linux | cups-client Ubuntu 24.04.5 LTS (noble) | 2.4.7-1.2ubuntu7.13 | [cups-client 2.4.7-1.2ubuntu7.13](https://patchblox.com/security/data/fix/linux/ubuntu-noble-cups-client-2.4.7-1.2ubuntu7.13.md) | Apr 24, 2026 |
| Linux | cups-client Ubuntu 25.10 (questing) | 2.4.12-0ubuntu3.9 | [cups-client 2.4.12-0ubuntu3.9](https://patchblox.com/security/data/fix/linux/ubuntu-questing-cups-client-2.4.12-0ubuntu3.9.md) | Apr 24, 2026 |
| Linux | cups-client Ubuntu 26.04.1 LTS (resolute) | 2.4.16-1ubuntu1.2 | [cups-client 2.4.16-1ubuntu1.2](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-cups-client-2.4.16-1ubuntu1.2.md) | Apr 24, 2026 |
| Linux | cups-client amzn 2023 | 1:2.4.16-1.amzn2023.0.3 | [ALAS2023-2026-1635](https://patchblox.com/security/data/fix/linux/alas2023-2026-1635.md) | Apr 27, 2026 |
| Linux | cups-client-debuginfo amzn 2023 | 1:2.4.16-1.amzn2023.0.3 | [ALAS2023-2026-1635](https://patchblox.com/security/data/fix/linux/alas2023-2026-1635.md) | Apr 27, 2026 |
| Linux | cups-common Ubuntu 22.04.1 LTS (jammy) | 2.4.1op1-1ubuntu4.20 | [cups-common 2.4.1op1-1ubuntu4.20](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-cups-common-2.4.1op1-1ubuntu4.20.md) | Apr 24, 2026 |
| Linux | cups-common Ubuntu 24.04.5 LTS (noble) | 2.4.7-1.2ubuntu7.13 | [cups-common 2.4.7-1.2ubuntu7.13](https://patchblox.com/security/data/fix/linux/ubuntu-noble-cups-common-2.4.7-1.2ubuntu7.13.md) | Apr 24, 2026 |
| Linux | cups-common Ubuntu 25.10 (questing) | 2.4.12-0ubuntu3.9 | [cups-common 2.4.12-0ubuntu3.9](https://patchblox.com/security/data/fix/linux/ubuntu-questing-cups-common-2.4.12-0ubuntu3.9.md) | Apr 24, 2026 |
| Linux | cups-common Ubuntu 26.04.1 LTS (resolute) | 2.4.16-1ubuntu1.2 | [cups-common 2.4.16-1ubuntu1.2](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-cups-common-2.4.16-1ubuntu1.2.md) | Apr 24, 2026 |
| Linux | cups-core-drivers Ubuntu 22.04.1 LTS (jammy) | 2.4.1op1-1ubuntu4.20 | [cups-core-drivers 2.4.1op1-1ubuntu4.20](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-cups-core-drivers-2.4.1op1-1ubuntu4.20.md) | Apr 24, 2026 |
| Linux | cups-core-drivers Ubuntu 24.04.5 LTS (noble) | 2.4.7-1.2ubuntu7.13 | [cups-core-drivers 2.4.7-1.2ubuntu7.13](https://patchblox.com/security/data/fix/linux/ubuntu-noble-cups-core-drivers-2.4.7-1.2ubuntu7.13.md) | Apr 24, 2026 |
| Linux | cups-core-drivers Ubuntu 25.10 (questing) | 2.4.12-0ubuntu3.9 | [cups-core-drivers 2.4.12-0ubuntu3.9](https://patchblox.com/security/data/fix/linux/ubuntu-questing-cups-core-drivers-2.4.12-0ubuntu3.9.md) | Apr 24, 2026 |
| Linux | cups-core-drivers Ubuntu 26.04.1 LTS (resolute) | 2.4.16-1ubuntu1.2 | [cups-core-drivers 2.4.16-1ubuntu1.2](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-cups-core-drivers-2.4.16-1ubuntu1.2.md) | Apr 24, 2026 |
| Linux | cups-daemon Ubuntu 22.04.1 LTS (jammy) | 2.4.1op1-1ubuntu4.20 | [cups-daemon 2.4.1op1-1ubuntu4.20](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-cups-daemon-2.4.1op1-1ubuntu4.20.md) | Apr 24, 2026 |
| Linux | cups-daemon Ubuntu 24.04.5 LTS (noble) | 2.4.7-1.2ubuntu7.13 | [cups-daemon 2.4.7-1.2ubuntu7.13](https://patchblox.com/security/data/fix/linux/ubuntu-noble-cups-daemon-2.4.7-1.2ubuntu7.13.md) | Apr 24, 2026 |
| Linux | cups-daemon Ubuntu 25.10 (questing) | 2.4.12-0ubuntu3.9 | [cups-daemon 2.4.12-0ubuntu3.9](https://patchblox.com/security/data/fix/linux/ubuntu-questing-cups-daemon-2.4.12-0ubuntu3.9.md) | Apr 24, 2026 |
| Linux | cups-daemon Ubuntu 26.04.1 LTS (resolute) | 2.4.16-1ubuntu1.2 | [cups-daemon 2.4.16-1ubuntu1.2](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-cups-daemon-2.4.16-1ubuntu1.2.md) | Apr 24, 2026 |
| Linux | cups-debuginfo amzn 2023 | 1:2.4.16-1.amzn2023.0.3 | [ALAS2023-2026-1635](https://patchblox.com/security/data/fix/linux/alas2023-2026-1635.md) | Apr 27, 2026 |
| Linux | cups-debugsource amzn 2023 | 1:2.4.16-1.amzn2023.0.3 | [ALAS2023-2026-1635](https://patchblox.com/security/data/fix/linux/alas2023-2026-1635.md) | Apr 27, 2026 |
| Linux | cups-devel amzn 2023 | 1:2.4.16-1.amzn2023.0.3 | [ALAS2023-2026-1635](https://patchblox.com/security/data/fix/linux/alas2023-2026-1635.md) | Apr 27, 2026 |
| Linux | cups-filesystem amzn 2023 | 1:2.4.16-1.amzn2023.0.3 | [ALAS2023-2026-1635](https://patchblox.com/security/data/fix/linux/alas2023-2026-1635.md) | Apr 27, 2026 |
| Linux | cups-ipp-utils Ubuntu 22.04.1 LTS (jammy) | 2.4.1op1-1ubuntu4.20 | [cups-ipp-utils 2.4.1op1-1ubuntu4.20](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-cups-ipp-utils-2.4.1op1-1ubuntu4.20.md) | Apr 24, 2026 |
| Linux | cups-ipp-utils Ubuntu 24.04.5 LTS (noble) | 2.4.7-1.2ubuntu7.13 | [cups-ipp-utils 2.4.7-1.2ubuntu7.13](https://patchblox.com/security/data/fix/linux/ubuntu-noble-cups-ipp-utils-2.4.7-1.2ubuntu7.13.md) | Apr 24, 2026 |
| Linux | cups-ipp-utils Ubuntu 25.10 (questing) | 2.4.12-0ubuntu3.9 | [cups-ipp-utils 2.4.12-0ubuntu3.9](https://patchblox.com/security/data/fix/linux/ubuntu-questing-cups-ipp-utils-2.4.12-0ubuntu3.9.md) | Apr 24, 2026 |
| Linux | cups-ipp-utils Ubuntu 26.04.1 LTS (resolute) | 2.4.16-1ubuntu1.2 | [cups-ipp-utils 2.4.16-1ubuntu1.2](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-cups-ipp-utils-2.4.16-1ubuntu1.2.md) | Apr 24, 2026 |
| Linux | cups-ipptool amzn 2023 | 1:2.4.16-1.amzn2023.0.3 | [ALAS2023-2026-1635](https://patchblox.com/security/data/fix/linux/alas2023-2026-1635.md) | Apr 27, 2026 |
| Linux | cups-ipptool-debuginfo amzn 2023 | 1:2.4.16-1.amzn2023.0.3 | [ALAS2023-2026-1635](https://patchblox.com/security/data/fix/linux/alas2023-2026-1635.md) | Apr 27, 2026 |
| Linux | cups-libs amzn 2023 | 1:2.4.16-1.amzn2023.0.3 | [ALAS2023-2026-1635](https://patchblox.com/security/data/fix/linux/alas2023-2026-1635.md) | Apr 27, 2026 |
| Linux | cups-libs-debuginfo amzn 2023 | 1:2.4.16-1.amzn2023.0.3 | [ALAS2023-2026-1635](https://patchblox.com/security/data/fix/linux/alas2023-2026-1635.md) | Apr 27, 2026 |
| Linux | cups-lpd amzn 2023 | 1:2.4.16-1.amzn2023.0.3 | [ALAS2023-2026-1635](https://patchblox.com/security/data/fix/linux/alas2023-2026-1635.md) | Apr 27, 2026 |
| Linux | cups-lpd-debuginfo amzn 2023 | 1:2.4.16-1.amzn2023.0.3 | [ALAS2023-2026-1635](https://patchblox.com/security/data/fix/linux/alas2023-2026-1635.md) | Apr 27, 2026 |
| Linux | cups-ppdc Ubuntu 22.04.1 LTS (jammy) | 2.4.1op1-1ubuntu4.20 | [cups-ppdc 2.4.1op1-1ubuntu4.20](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-cups-ppdc-2.4.1op1-1ubuntu4.20.md) | Apr 24, 2026 |
| Linux | cups-ppdc Ubuntu 24.04.5 LTS (noble) | 2.4.7-1.2ubuntu7.13 | [cups-ppdc 2.4.7-1.2ubuntu7.13](https://patchblox.com/security/data/fix/linux/ubuntu-noble-cups-ppdc-2.4.7-1.2ubuntu7.13.md) | Apr 24, 2026 |
| Linux | cups-ppdc Ubuntu 25.10 (questing) | 2.4.12-0ubuntu3.9 | [cups-ppdc 2.4.12-0ubuntu3.9](https://patchblox.com/security/data/fix/linux/ubuntu-questing-cups-ppdc-2.4.12-0ubuntu3.9.md) | Apr 24, 2026 |
| Linux | cups-ppdc Ubuntu 26.04.1 LTS (resolute) | 2.4.16-1ubuntu1.2 | [cups-ppdc 2.4.16-1ubuntu1.2](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-cups-ppdc-2.4.16-1ubuntu1.2.md) | Apr 24, 2026 |
| Linux | cups-printerapp amzn 2023 | 1:2.4.16-1.amzn2023.0.3 | [ALAS2023-2026-1635](https://patchblox.com/security/data/fix/linux/alas2023-2026-1635.md) | Apr 27, 2026 |
| Linux | cups-printerapp-debuginfo amzn 2023 | 1:2.4.16-1.amzn2023.0.3 | [ALAS2023-2026-1635](https://patchblox.com/security/data/fix/linux/alas2023-2026-1635.md) | Apr 27, 2026 |
| Linux | cups-server-common Ubuntu 22.04.1 LTS (jammy) | 2.4.1op1-1ubuntu4.20 | [cups-server-common 2.4.1op1-1ubuntu4.20](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-cups-server-common-2.4.1op1-1ubuntu4.20.md) | Apr 24, 2026 |
| Linux | cups-server-common Ubuntu 24.04.5 LTS (noble) | 2.4.7-1.2ubuntu7.13 | [cups-server-common 2.4.7-1.2ubuntu7.13](https://patchblox.com/security/data/fix/linux/ubuntu-noble-cups-server-common-2.4.7-1.2ubuntu7.13.md) | Apr 24, 2026 |
| Linux | cups-server-common Ubuntu 25.10 (questing) | 2.4.12-0ubuntu3.9 | [cups-server-common 2.4.12-0ubuntu3.9](https://patchblox.com/security/data/fix/linux/ubuntu-questing-cups-server-common-2.4.12-0ubuntu3.9.md) | Apr 24, 2026 |
| Linux | cups-server-common Ubuntu 26.04.1 LTS (resolute) | 2.4.16-1ubuntu1.2 | [cups-server-common 2.4.16-1ubuntu1.2](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-cups-server-common-2.4.16-1ubuntu1.2.md) | Apr 24, 2026 |
| Linux | libcups2 Ubuntu 22.04.1 LTS (jammy) | 2.4.1op1-1ubuntu4.20 | [libcups2 2.4.1op1-1ubuntu4.20](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-libcups2-2.4.1op1-1ubuntu4.20.md) | Apr 24, 2026 |
| Linux | libcups2t64 Ubuntu 24.04.5 LTS (noble) | 2.4.7-1.2ubuntu7.13 | [libcups2t64 2.4.7-1.2ubuntu7.13](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libcups2t64-2.4.7-1.2ubuntu7.13.md) | Apr 24, 2026 |
| Linux | libcups2t64 Ubuntu 25.10 (questing) | 2.4.12-0ubuntu3.9 | [libcups2t64 2.4.12-0ubuntu3.9](https://patchblox.com/security/data/fix/linux/ubuntu-questing-libcups2t64-2.4.12-0ubuntu3.9.md) | Apr 24, 2026 |
| Linux | libcups2t64 Ubuntu 26.04.1 LTS (resolute) | 2.4.16-1ubuntu1.2 | [libcups2t64 2.4.16-1ubuntu1.2](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-libcups2t64-2.4.16-1ubuntu1.2.md) | Apr 24, 2026 |
| Linux | libcupsimage2 Ubuntu 22.04.1 LTS (jammy) | 2.4.1op1-1ubuntu4.20 | [libcupsimage2 2.4.1op1-1ubuntu4.20](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-libcupsimage2-2.4.1op1-1ubuntu4.20.md) | Apr 24, 2026 |
| Linux | libcupsimage2t64 Ubuntu 24.04.5 LTS (noble) | 2.4.7-1.2ubuntu7.13 | [libcupsimage2t64 2.4.7-1.2ubuntu7.13](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libcupsimage2t64-2.4.7-1.2ubuntu7.13.md) | Apr 24, 2026 |
| Linux | libcupsimage2t64 Ubuntu 25.10 (questing) | 2.4.12-0ubuntu3.9 | [libcupsimage2t64 2.4.12-0ubuntu3.9](https://patchblox.com/security/data/fix/linux/ubuntu-questing-libcupsimage2t64-2.4.12-0ubuntu3.9.md) | Apr 24, 2026 |
| Linux | libcupsimage2t64 Ubuntu 26.04.1 LTS (resolute) | 2.4.16-1ubuntu1.2 | [libcupsimage2t64 2.4.16-1ubuntu1.2](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-libcupsimage2t64-2.4.16-1ubuntu1.2.md) | Apr 24, 2026 |

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Data as of 2026-11-09T01:18:40Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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