CVE-2026-88051 tesseract-ocr CVE debrief

Who should care

Defenders responsible for Tesseract installations, developers using Tesseract in their applications, and security teams monitoring for potential exploitation should assess exposure and prioritize verification and updates. They should review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance, and plan vendor-supported updates or mitigations through normal change control where exposure is confirmed.

Why it matters

CVE-2026-88051 is a high-severity vulnerability in the Tesseract OCR engine that can cause heap corruption and crashes. Defenders should prioritize verifying and updating Tesseract installations to prevent potential exploitation.

• Potential heap corruption and crashes
• Possible controlled corruption of FontInfo structures
• Verification of Tesseract installations required
• Update to fixed release necessary when available

Technical summary

The GenericVector::read callback in Tesseract OCR engine version 5.5.3 and earlier is vulnerable to a heap out-of-bounds write when processing a crafted TESSDATA_INTTEMP component. The vulnerability arises from the lack of proper validation of the size_used_ field from a .traineddata model, allowing an attacker to cause heap corruption, crashes, or potentially controlled corruption of FontInfo structures. The issue is caused by the callback form of GenericVector::read in src/ccutil/genericvector.h, which reads the independent int32 fields reserved and size_used_ from a .traineddata model without a cap or an invariant check.

Defensive priority

Defenders should prioritize verifying and updating Tesseract installations to prevent potential heap corruption and crashes.

Recommended defensive actions

• Verify Tesseract installations for potential exposure
• Update Tesseract to a fixed release when available
• Monitor for suspicious activity related to Tesseract usage
• Review compensating controls for exposed systems while remediation is scheduled and verified
• 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
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The CVE record and NVD entry provide details on the vulnerability, but a fixed release is not available as of this review. The vulnerability is caused by the GenericVector::read callback in Tesseract OCR engine version 5.5.3 and earlier, which reads the independent int32 fields reserved and size_used_ from a .traineddata model without a cap or an invariant check. The TESSDATA_INTTEMP component can be crafted to set reserved to a small value and size_used_ to a large value, leading to a heap out-of-bounds write of FontInfo structures.

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.