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.
CVE-2026-34978
This medium-severity CVE scores 6.5 under NVD CVSS v3. EPSS exploit probability: 0.0%, top 90% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).
- Lower severity and no public exploit yet
A fix is available — apply it.
- CVSS v3
- 6.5
- EG Score
- 6.5(medium)
- EPSS
- 32.9%
- KEV
- Not listed
Published
April 3, 2026
Last Modified
April 16, 2026
References (2)
- security-advisories@githubhttps://github.com/OpenPrinting/cups/security/advisories/GHSA-f53q-7mxp-9gcr
- 134c704f-9b21-4f2e-91b3-4a467353bcc0https://github.com/OpenPrinting/cups/security/advisories/GHSA-f53q-7mxp-9gcr
Vendor Advisories for CVE-2026-34978(2)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
- CVE-2026-34978Microsoft Security Response Center (MSRC)Medium
OpenPrinting CUPS: Path traversal in RSS notify-recipient-uri enables file write outside CacheDir/rss (and clobbering of job.cache)
- RHSA-2026:8814Red Hat Product SecurityHigh
Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update
Patch Availability(2)
| Vendor / Ecosystem | Fixed in / Patch | Released | Source |
|---|---|---|---|
| ubuntu | libcupsimage2t64 (2.4.16-1ubuntu1.2) @ resolute | 2026-06-11 | ubuntu |
| redhat | cups-main-2.4.17-1.hum1 | 2026-04-17 | redhat |
Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Additional Vendor Advisories
(1)
Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.
Data Freshness Timeline
(refreshed 10× in last 7d / 43× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-07-16 17:03 UTCEPSS rescore
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- 2026-06-11 21:53 UTCVendor advisory
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- 2026-06-10 13:35 UTCEG score recompute
- 2026-06-10 13:35 UTCVendor advisory
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- 2026-06-09 14:25 UTCVendor advisory
- 2026-06-08 14:17 UTCEPSS rescore
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- 2026-06-08 08:42 UTCEG score recompute
- 2026-06-08 08:42 UTCVendor advisory
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- 2026-06-07 10:48 UTCVendor advisory
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- 2026-05-20 19:10 UTCVendor advisory
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