OpenPrinting CUPS: Path traversal in RSS notify-recipient-uri enables file write outside CacheDir/rss (and clobbering of job.cache)
OpenPrinting · cups
Official source article: GitHub GHSA-F53Q-7MXP-9GCR ↗. Check the applicable product and release in the original source.
6.5MediumCVSS 3.1
Recommended action
Patch only the product branches with a verified fix
Medium technical severity with public exploit material referenced by a structured source; prioritise exposed affected systems while verifying vendor guidance. Verified remediation exists for at least one product or source, but 2 structured product or package states remain unresolved. Apply remediation only to the exact product branch confirmed by its source.
Published severityMedium→Operational priority:High, raised one band.upgradedsince 6 Apr 2026
Evidence used
No CISA KEV confirmation is currently recorded.
A structured source references public exploit or proof-of-concept material.
The selected CVSS metric records a network-reachable, unauthenticated path with no user interaction.
EPSS is 0.42% for the current model date.
Compensating controls
Validate the affected product branch and deploy the verified fixed release.
Restrict the affected network interface to trusted sources where business-safe.
Increase monitoring for the attack path and post-exploitation behaviour described in the report.
Verification
Confirm that the asset runs OpenPrinting cups and falls inside the recorded affected range.
Verify the installed build against the product-specific fixed version after deployment.
Validate exposure, authentication requirements and compensating controls in the actual environment.
Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Cross-source reconciliation
Remediation availability differs by product scope
Verified remediation exists for at least one product or source, but 2 structured product or package states remain unresolved. Apply remediation only to the exact product branch confirmed by its source.
Debian Security Tracker: 2 affected package states with no published fix
Distribution package intelligence
Release-specific package status
Alpine, Debian, ubuntu findings are scoped to the named distribution, release and source package. An absent finding does not mean a package is unaffected.
8 package states
Package result overrides the generic status
BlackTree has verified remediation for at least one product or source, but the relevant distribution still reports no fixed package for 2 affected package states shown here. Treat those rows as affected with no fix until that distribution publishes a fixed version.
Repository candidate not checked
A published vendor fix does not prove that a matching update is enabled and installable on a particular asset. Confirm the local package candidate before scheduling remediation.
Distribution release
Source package
Vendor state
Fixed version
Evidence
Alpine v3.23v3.23 · main
cups
Vendor fix publishedAlpine records a security fix at this version. An absent entry does not mean the package is unaffected.
Vendor fix publishedCanonical reports that a fixed source package version has been published. Repository candidate availability is not checked by BlackTree.
Structured product status and remediation from the issuing vendor. Product-state explanations are always visible; large lists can be searched or downloaded.
1 current
CVE-2026-34978 · CSAF 2.0 · revision 3 · finalRed Hat Product Securitycups: OpenPrinting CUPS: Denial of Service via path traversal in RSS notifier
41 known affected
The vendor explicitly identifies these products as affected by this CVE.
cups as a component of Red Hat Enterprise Linux 10
cups-client as a component of Red Hat Enterprise Linux 10
cups-devel as a component of Red Hat Enterprise Linux 10
cups-filesystem as a component of Red Hat Enterprise Linux 10
cups-ipptool as a component of Red Hat Enterprise Linux 10
cups-libs as a component of Red Hat Enterprise Linux 10
cups-lpd as a component of Red Hat Enterprise Linux 10
cups-printerapp as a component of Red Hat Enterprise Linux 10
cups.src as a component of Red Hat Enterprise Linux 10
cups as a component of Red Hat Enterprise Linux 6
cups-devel as a component of Red Hat Enterprise Linux 6
cups-libs as a component of Red Hat Enterprise Linux 6
Summary
A flaw was found in OpenPrinting CUPS. A remote attacker can exploit a path traversal vulnerability in the RSS notifier by manipulating the `notify-recipient-uri`. This allows writing arbitrary RSS XML data to sensitive files outside the intended directory. This can lead to a denial of service (DoS) by corrupting critical system files, such as the job cache, causing the scheduler to fail and previously queued jobs to disappear.
Remediation
For details on how to apply this update, which includes the changes described in this advisory, refer to: https://images.redhat.com/
Optional official sources
National CERT insights ?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.
Choose official national sources for this report. Each advisory shows its original language. Your selection is remembered on this device and included in shared links.
Official European source
ENISA European Vulnerability Database
Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.
1 current
ENISA EUVD identifier
EUVD-2026-18884
No EUVD known-exploited evidence
ENISA has published the identifier mapping but no EUVD description has been stored yet.
EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
Not supplied in the stored EUVD record
Advisory evidence
No linked advisory details stored yet
Recommended actionPatch only the product branches with a verified fix
Medium technical severity with public exploit material referenced by a structured source; prioritise exposed affected systems while verifying vendor guidance. Verified remediation exists for at least one product or source, but 2 structured product or package states remain unresolved. Apply remediation only to the exact product branch confirmed by its source.
Fix availability varies by product
01
What, why and how
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
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.
Why
Attacker-controlled path data is not constrained to the intended directory before the application accesses a file.
How
An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.
What
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.
Why
Attacker-controlled path data is not constrained to the intended directory before the application accesses a file.
How
An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.
02
Exploit reality and attack path
CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.
Observed exploitation ?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.No confirmed evidence
No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.
Public PoC / exploit material ?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.Reference recorded
A structured CVE source labels at least one public reference as exploit material. BlackTree has not independently validated that it is safe, reliable or weaponised.
Likely attack path
a network path → Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface
Network
Privileges required
None: unauthenticated exploitation is possible
User interaction
None
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Unchanged: impact remains within the vulnerable component's security authority
Weakness ?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal'). The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.
CVSS vector ?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L
Common Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.
AVNetworkAttack vector: The vulnerable component can be reached over a network.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRNonePrivileges required: The attacker does not need an account or existing privileges.UINoneUser interaction: No action by another user is required.SUnchangedScope: The security impact remains within the vulnerable component's authority.CNoneConfidentiality impact: No direct loss is represented by this metric.ILowIntegrity impact: A successful attack can cause a limited loss.ALowAvailability impact: A successful attack can cause a limited loss.
Post-exploitation / living off the land
No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.
Ein Angreifer kann mehrere Schwachstellen in CUPS ausnutzen, um Sicherheitsvorkehrungen zu umgehen, beliebigen Code auszuführen, erweiterte Rechte zu erlangen, Daten zu manipulieren oder einen Denial-of-Service-Zustand herbeizuführen.
Official advisory ↗CERT-FR · French · CERTFR-2026-AVI-0463Multiples vulnérabilités dans les produits Microsoft
des indicateurs de
compromission
Flux RSS des durcissement et
recommandations
Flux RSS des bulletins
d'actualité
Premier Ministre
S.G.D.S.N
Agence nationale
de la sécurité des
systèmes d'information
Paris, le 20 avril 2026
N° CERTFR-2026-AVI-0463
Affaire suivie par: CERT-FR
Avis du CERT-FR
Objet: Multiples vulnérabilités dans les produits Microsoft
Gestion du document
Référence
CERTFR-2026-AVI-0463
Titre
Multiples vulnérabilités dans les produits Microsoft
Date de la première version 20 avril 2026
Date de la dernière version 20 avril 2026
Source(s)
Bulletin de sécurité Microsoft CVE-2026-27447 du 05 avril 2026
Bulletin de sécurité Microsoft CVE-2026-34978 du 05 avril 2026
Bulletin de sécurité Microsoft CVE-2026-34979 du 05 avril 2026
Bulletin de sécurité Microsoft CVE-2026-34980 du 05 avril 2026
Bulletin de sécurité Microsoft CVE-2026-34990 du 05 avril 2026
Bulletin de sécurité Microsoft CVE-2026-31408 du 07 avril 2026
Bulletin de sécurité Microsoft CVE-2026-34445 du 09 avril 2026
Bulletin de sécurité Microsoft CVE-2026-34446 du 09 avril 2026
Bulletin de sécurité Microsoft CVE-2026-39314 du 09 avril 2026
Bulletin de sécurité Microsoft CVE-2026-39316 du 09 avril 2026
Bulletin de sécurité Microsoft CVE-2026-31414 du 14 avril 2026
Bulletin de sécurité Microsoft CVE-2026-31416 du 14 avril 2026
Bu
Official advisory ↗JVN iPedia · Japanese · JVNDB-2026-011716OpenPrintingのCUPSにおけるパストラバーサルの脆弱性
Operational remediation based on structured source evidence.
Status ?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Use the product-specific evidence above. Patch only products with a verified fixed release, and keep every affected or under-investigation state without a matching fix in the remediation queue.
Workaround
No verified workaround is recorded. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.
04
Evidence and provenance
Published 3 Apr 2026 · Last source change 6 Apr 2026, 15:42 UTC · CWE-22 · Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
CVE recordCVE.org · 5.2
CVSS sourceCNA
EPSS source ?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.FIRST · tracked since 2026-08-14
European sourceENISA EUVD · EUVD-2026-18884
Product sourceVendor CSAF · Red Hat Product Security
Remediation sourceVendor CSAF · Red Hat Product Security
CWE sourceCNA
NVD statusNVD enriched
Core structured fields are present and their contributing authorities are shown above.
Affected versionsThe structured affected or fixed version information changed.
Before
<= 2.4.16 · Fixed: No fixed version is explicitly recorded in the structured CVE data.
After
<= 2.4.16 · Fixed: For details on how to apply this update, which includes the changes described in this advisory, refer to: https://images.redhat.com/
Affected versionsThe structured affected or fixed version information changed.
Before
cups as a component of Red Hat Enterprise Linux 10; cups-client as a component of Red Hat Enterprise Linux 10; cups-devel as a component of Red Hat Enterprise Linux 10; cups-filesystem as a component of Red Hat Enterprise Linux 10; cups-ipptool as a component of Red Hat Enterprise Linux 10; cups-libs as a component of Red Hat Enterprise Linux 10; cups-lpd as a component of Red Hat Enterprise Linux 10; cups-printerapp as a component of Red Hat Enterprise Linux 10; cups.src as a component of Red Hat Enterprise Linux 10; cups as a component of Red Hat Enterprise Linux 6; cups-devel as a component of Red Hat Enterprise Linux 6; cups-libs as a component of Red Hat Enterprise Linux 6; cups-lpd as a component of Red Hat Enterprise Linux 6; cups-php as a component of Red Hat Enterprise Linux 6; cups.src as a component of Red Hat Enterprise Linux 6; cups as a component of Red Hat Enterprise Linux 7; cups-client as a component of Red Hat Enterprise Linux 7; cups-devel as a component of Red Hat Enterprise Linux 7; cups-filesystem as a component of Red Hat Enterprise Linux 7; cups-ipptool as a component of Red Hat Enterprise Linux 7; cups-libs as a component of Red Hat Enterprise Linux 7; cups-lpd as a component of Red Hat Enterprise Linux 7; cups.src as a component of Red Hat Enterprise Linux 7; cups as a component of Red Hat Enterprise Linux 8; cups-client as a component of Red Hat Enterprise Linux 8; cups-devel as a component of Red Hat Enterprise Linux 8; cups-filesystem as a component of Red Hat Enterprise Linux 8; cups-ipptool as a component of Red Hat Enterprise Linux 8; cups-libs as a component of Red Hat Enterprise Linux 8; cups-lpd as a component of Red Hat Enterprise Linux 8; and 10 more · Fixed: cups-main@aarch64 as a component of Red Hat Hardened Images; cups-main@noarch as a component of Red Hat Hardened Images; cups-main@src as a component of Red Hat Hardened Images; cups-main@x86_64 as a component of Red Hat Hardened Images
After
cups as a component of Red Hat Enterprise Linux 10; cups-client as a component of Red Hat Enterprise Linux 10; cups-devel as a component of Red Hat Enterprise Linux 10; cups-filesystem as a component of Red Hat Enterprise Linux 10; cups-ipptool as a component of Red Hat Enterprise Linux 10; cups-libs as a component of Red Hat Enterprise Linux 10; cups-lpd as a component of Red Hat Enterprise Linux 10; cups-printerapp as a component of Red Hat Enterprise Linux 10; cups.src as a component of Red Hat Enterprise Linux 10; cups as a component of Red Hat Enterprise Linux 6; cups-devel as a component of Red Hat Enterprise Linux 6; cups-libs as a component of Red Hat Enterprise Linux 6; cups-lpd as a component of Red Hat Enterprise Linux 6; cups-php as a component of Red Hat Enterprise Linux 6; cups.src as a component of Red Hat Enterprise Linux 6; cups as a component of Red Hat Enterprise Linux 7; cups-client as a component of Red Hat Enterprise Linux 7; cups-devel as a component of Red Hat Enterprise Linux 7; cups-filesystem as a component of Red Hat Enterprise Linux 7; cups-ipptool as a component of Red Hat Enterprise Linux 7; cups-libs as a component of Red Hat Enterprise Linux 7; cups-lpd as a component of Red Hat Enterprise Linux 7; cups.src as a component of Red Hat Enterprise Linux 7; cups as a component of Red Hat Enterprise Linux 8; cups-client as a component of Red Hat Enterprise Linux 8; cups-devel as a component of Red Hat Enterprise Linux 8; cups-filesystem as a component of Red Hat Enterprise Linux 8; cups-ipptool as a component of Red Hat Enterprise Linux 8; cups-libs as a component of Red Hat Enterprise Linux 8; cups-lpd as a component of Red Hat Enterprise Linux 8; and 11 more · Fixed: cups-main@aarch64 as a component of Red Hat Hardened Images; cups-main@noarch as a component of Red Hat Hardened Images; cups-main@src as a component of Red Hat Hardened Images; cups-main@x86_64 as a component of Red Hat Hardened Images
Affected versionsThe structured affected or fixed version information changed.
Before
cups as a component of Red Hat Enterprise Linux 10; cups-client as a component of Red Hat Enterprise Linux 10; cups-devel as a component of Red Hat Enterprise Linux 10; cups-filesystem as a component of Red Hat Enterprise Linux 10; cups-ipptool as a component of Red Hat Enterprise Linux 10; cups-libs as a component of Red Hat Enterprise Linux 10; cups-lpd as a component of Red Hat Enterprise Linux 10; cups-printerapp as a component of Red Hat Enterprise Linux 10; cups.src as a component of Red Hat Enterprise Linux 10; cups as a component of Red Hat Enterprise Linux 6; cups-devel as a component of Red Hat Enterprise Linux 6; cups-libs as a component of Red Hat Enterprise Linux 6; cups-lpd as a component of Red Hat Enterprise Linux 6; cups-php as a component of Red Hat Enterprise Linux 6; cups.src as a component of Red Hat Enterprise Linux 6; cups as a component of Red Hat Enterprise Linux 7; cups-client as a component of Red Hat Enterprise Linux 7; cups-devel as a component of Red Hat Enterprise Linux 7; cups-filesystem as a component of Red Hat Enterprise Linux 7; cups-ipptool as a component of Red Hat Enterprise Linux 7; cups-libs as a component of Red Hat Enterprise Linux 7; cups-lpd as a component of Red Hat Enterprise Linux 7; cups.src as a component of Red Hat Enterprise Linux 7; cups as a component of Red Hat Enterprise Linux 8; cups-client as a component of Red Hat Enterprise Linux 8; cups-devel as a component of Red Hat Enterprise Linux 8; cups-filesystem as a component of Red Hat Enterprise Linux 8; cups-ipptool as a component of Red Hat Enterprise Linux 8; cups-libs as a component of Red Hat Enterprise Linux 8; cups-lpd as a component of Red Hat Enterprise Linux 8; and 11 more · Fixed: cups-main@aarch64 as a component of Red Hat Hardened Images; cups-main@noarch as a component of Red Hat Hardened Images; cups-main@src as a component of Red Hat Hardened Images; cups-main@x86_64 as a component of Red Hat Hardened Images
After
cups as a component of Red Hat Enterprise Linux 10; cups-client as a component of Red Hat Enterprise Linux 10; cups-devel as a component of Red Hat Enterprise Linux 10; cups-filesystem as a component of Red Hat Enterprise Linux 10; cups-ipptool as a component of Red Hat Enterprise Linux 10; cups-libs as a component of Red Hat Enterprise Linux 10; cups-lpd as a component of Red Hat Enterprise Linux 10; cups-printerapp as a component of Red Hat Enterprise Linux 10; cups.src as a component of Red Hat Enterprise Linux 10; cups as a component of Red Hat Enterprise Linux 6; cups-devel as a component of Red Hat Enterprise Linux 6; cups-libs as a component of Red Hat Enterprise Linux 6; cups-lpd as a component of Red Hat Enterprise Linux 6; cups-php as a component of Red Hat Enterprise Linux 6; cups.src as a component of Red Hat Enterprise Linux 6; cups as a component of Red Hat Enterprise Linux 7; cups-client as a component of Red Hat Enterprise Linux 7; cups-devel as a component of Red Hat Enterprise Linux 7; cups-filesystem as a component of Red Hat Enterprise Linux 7; cups-ipptool as a component of Red Hat Enterprise Linux 7; cups-libs as a component of Red Hat Enterprise Linux 7; cups-lpd as a component of Red Hat Enterprise Linux 7; cups.src as a component of Red Hat Enterprise Linux 7; cups as a component of Red Hat Enterprise Linux 8; cups-client as a component of Red Hat Enterprise Linux 8; cups-devel as a component of Red Hat Enterprise Linux 8; cups-filesystem as a component of Red Hat Enterprise Linux 8; cups-ipptool as a component of Red Hat Enterprise Linux 8; cups-libs as a component of Red Hat Enterprise Linux 8; cups-lpd as a component of Red Hat Enterprise Linux 8; and 10 more · Fixed: cups-main@aarch64 as a component of Red Hat Hardened Images; cups-main@noarch as a component of Red Hat Hardened Images; cups-main@src as a component of Red Hat Hardened Images; cups-main@x86_64 as a component of Red Hat Hardened Images
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.