CVE-2026-18495 Red Hat CVE debrief

Who should care

Defenders responsible for systems and applications using libtiff's `tiff2pdf` utility should assess exposure and apply remediation or patches provided by the vendor. This includes operators, platform administrators, vulnerability management teams, and security teams who need to verify if systems and applications using libtiff's `tiff2pdf` utility are vulnerable and apply remediation or patches provided by the vendor.

Why it matters

CVE-2026-18495 is a medium-severity vulnerability in libtiff's `tiff2pdf` utility that can cause severe memory corruption and crash. Defenders should assess exposure and apply remediation or patches provided by the vendor.

• Verify if systems and applications using libtiff's `tiff2pdf` utility are vulnerable
• Assess the risk of severe memory corruption and crash
• Apply remediation or patches provided by the vendor, if available

Technical summary

The vulnerability exists in the `tiff2pdf` utility of libtiff due to an integer truncation error when processing crafted BigTIFF files. This can cause a 64-bit `StripByteCounts` value to be truncated to a 32-bit integer, leading to an undersized memory allocation and a subsequent out-of-bounds memory copy. The vulnerability can be triggered by providing a specially crafted BigTIFF file, which can lead to a crash and severe memory corruption. Defenders should assess exposure and apply remediation or patches provided by the vendor.

Defensive priority

Medium priority should be given to assessing exposure and applying remediation, as the vulnerability can lead to severe memory corruption and crash.

Recommended defensive actions

• Assess exposure of systems and applications using libtiff's `tiff2pdf` utility
• Verify if any compensating controls are in place to mitigate the vulnerability
• Apply remediation or patches provided by the vendor, if available
• Review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance
• Plan vendor-supported updates or mitigations through normal change control where exposure is confirmed
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented

Evidence notes

The CVE record and NVD detail page provide information on the vulnerability, including its description, CVSS score, and references. The vulnerability was reported by an anonymous researcher and has been assigned a medium severity score. The CVE record and NVD detail page also provide links to additional resources and references that may be useful for defenders. The vulnerability affects libtiff's `tiff2pdf` utility, and defenders should verify if systems and applications using this utility are vulnerable.

Sources and 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.