# CVE-2026-88345: flatcc schema lexer out-of-bounds read in string parsing

Source: https://junglewise.ai/threats/cve-2026-88345-an-out-of-bounds-read-vulnerability-exists-in-the-schema-lexer-of  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-22. Updated: 2026-09-26  
License: CC BY 4.0 with a link back

CVE-2026-88345 · Severity: high · CVSS 7.5 · Published 2026-09-22

flatcc is a FlatBuffers schema compiler. When processing a maliciously crafted schema file with an unterminated quotation mark at the end of the input, the lexer's string scanning logic reads one byte past the end of the input buffer. An attacker can trigger this vulnerability by submitting a specially crafted schema, causing the application to crash.

Technologies: [Dvidelabs Flatcc](https://junglewise.ai/threats/technologies/flatcc). Vendors: [Dvidelabs](https://junglewise.ai/threats/vendors/dvidelabs).

## Quick answers

**Is CVE-2026-88345 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-88345 being exploited in the wild.

**How severe is CVE-2026-88345?** High severity, with a CVSS score of 7.5, published 22 September 2026.

**Which products and versions are affected?** Dvidelabs Flatcc before 8581715e8ec4e5de8eea9fd6dad949e4dd7d0fa0.

**Is there a fix for CVE-2026-88345?** A patch was published on 2026-09-22: commit 8581715e8ec4e5de8eea9fd6dad949e4dd7d0fa0 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-88345 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-88345?** Check whether you run Dvidelabs Flatcc at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The vulnerability is an out-of-bounds read (CWE-122) in the lex() function's C-string scanning logic. When a schema reaches its end while inside an unterminated string literal, the pointer dereference (*p) occurs after p has exceeded the buffer boundary. A specially crafted schema can trigger this one-byte heap buffer over-read, resulting in denial of service through application crash.

## Affected products

- dvidelabs flatcc before 8581715e8ec4e5de8eea9fd6dad949e4dd7d0fa0

## Timeline

- 2026-09-22: disclosed
- 2026-09-22: patched: commit 8581715e8ec4e5de8eea9fd6dad949e4dd7d0fa0

## References

- [https://github.com/dvidelabs/flatcc/issues/385](https://github.com/dvidelabs/flatcc/issues/385)
- [https://github.com/jimjag/flatcc/commit/8581715e8ec4e5de8eea9fd6dad949e4dd7d0fa0](https://github.com/jimjag/flatcc/commit/8581715e8ec4e5de8eea9fd6dad949e4dd7d0fa0)

## Related threats

- [flatcc schema lexer out-of-bounds read](https://junglewise.ai/threats/cve-2026-88344-an-out-of-bounds-read-vulnerability-exists-in-the-schema-lexer-of)
- [Dvidelabs flatcc reachable assertion in align_order_members](https://junglewise.ai/threats/cve-2026-90786-dvidelabs-flatcc-reachable-assertion-in-align-order-members)
- [Dvidelabs flatcc reachable assertion in struct analysis](https://junglewise.ai/threats/cve-2026-90785-dvidelabs-flatcc-reachable-assertion-in-struct-analysis)
- [Dvidelabs flatcc memory leak in fb_clear_parser](https://junglewise.ai/threats/cve-2026-90784-dvidelabs-flatcc-memory-leak-in-fb-clear-parser)