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PatchSiren cyber security CVE debrief

CVE-2026-55480 OpenPrinting CVE debrief

OpenPrinting CUPS is vulnerable to a symlink attack. Prior to version 2.4.20, the copy_model() function in scheduler/ipp.c creates a predictable temporary file path in an lp-group-writable directory. An lp-group process can predict the connection-derived name and plant a symlink before a privileged add-printer or modify-printer operation triggers copy_model(). If the race succeeds, the root scheduler follows the symlink and truncates or overwrites a root-writable target with generated PPD data, compromising file integrity or availability.

Vendor
OpenPrinting
Product
cups
CVSS
MEDIUM 5.7
CISA KEV
Not listed in stored evidence
Original CVE published
2026-10-15
Original CVE updated
2026-10-20
Advisory published
2026-10-15
Advisory updated
2026-10-20

Who should care

Defenders managing Linux and Unix-like systems with OpenPrinting CUPS installations should assess exposure, especially in environments with multiple administrators managing lp-group privileges.

Why it matters

CVE-2026-55480 is a medium-severity vulnerability in OpenPrinting CUPS that allows an lp-group process to plant a symlink and potentially compromise file integrity or availability through a race condition. Defenders should verify exposure, assess lp-group privilege management, and apply patches or upgrade to version 2.4.20 or later.

  • File integrity compromise through symlink attack
  • Potential data loss or corruption
  • Elevation of privileges through exploitation
  • Verification of CUPS installation integrity required

Technical summary

The copy_model() function in scheduler/ipp.c of OpenPrinting CUPS creates a predictable temporary file path in an lp-group-writable directory. An lp-group process can predict the connection-derived name and plant a symlink before a privileged add-printer or modify-printer operation triggers copy_model(). Successful exploitation allows the root scheduler to follow the symlink and truncate or overwrite a root-writable target with generated PPD data, compromising file integrity or availability.

Defensive priority

Defenders should prioritize verifying exposure and assessing the integrity of their CUPS installations, especially in environments where lp-group privileges are managed by multiple administrators.

Recommended defensive actions

  • Verify CUPS version and assess exposure
  • Review lp-group privileges and manage access
  • Implement monitoring for suspicious printer operations
  • Apply patches or upgrade to version 2.4.20 or later
  • Track exceptions and retest remediated assets
  • Review compensating controls for exposed systems
  • Check relevant monitoring, detection, and logs for exposed assets that need extra review

Evidence notes

The CVE record and NVD entry provide details on the vulnerability, including its description, CVSS score, and affected versions. Patches and release notes are available from the OpenPrinting CUPS repository.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-55480 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-55480

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-55480 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-55480

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.