flatcc through 0.6.4 contains an integer overflow vulnerability in the check_header function of the FlatBuffers
Source GCVE Database
Not known to be exploited · CVSS 6.3 Medium.
Data as of 27 Oct 2026, 02:12 UTC
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 26 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| dvidelabsflatcc | Affected
| Fixed in– |
GitHubflatccpkg:github/flatccOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
Users should monitor the vendor advisory for updates. Until a fix is available, avoid processing untrusted FlatBuffers data with flatcc on 32-bit builds to mitigate risk.
Description
flatcc versions through 0.6.4 have an integer overflow vulnerability in the check_header function of the FlatBuffers verifier. The overflow guard code is ineffective, allowing crafted buffer offsets on 32-bit builds to bypass bounds checks. This can cause an out-of-bounds read before the buffer and lead to process crashes.
References
- nvd.nist.gov/vuln/detail/CVE-2026-116734 (opens in a new tab)
- github.com/dvidelabs/flatcc/commit/0df9c097a19badc8bd22d93af8fd47bd291e5d9f (opens in a new tab)
- github.com/dvidelabs/flatcc (opens in a new tab)
- github.com/dvidelabs/flatcc/blob/v0.6.4/src/runtime/verifier.c (opens in a new tab)
- hackmd.io/@haindpwn/flatcc-json-number-oob-read (opens in a new tab)
- vulncheck.com/advisories/flatcc-through-0.6.4-out-of-bounds-read-via-verifier-check-header (opens in a new tab)