Read the docs
TI-2026-80943 Aliases CVE-2026-116734GHSA-ch33-r734-vw2g

Integer overflow in flatcc verifier causes out-of-bounds read

Priority LOW 28CWE-190Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Attack requirements
Present
Impact type
—
Confidentiality · integrity · availability
None · None · Low
Fix status
No fix listed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA.

Summary

flatcc through 0.6.4 contains an integer overflow (CWE-190) in the check_header function of its FlatBuffers verifier. The overflow guard is dead code, so it never runs. On 32-bit builds, an attacker can supply a crafted buffer offset that wraps the bounds check, causing an out-of-bounds read before the buffer and crashing the process. The CVSS 4.0 base score is 6.3 (MEDIUM).

Written with Claude Haiku 5.5 from the sources below · 2026-10-28

Description from the CNA

flatcc through 0.6.4 contains an integer overflow vulnerability in the check_header function of the FlatBuffers verifier because its overflow guard is dead code. On 32-bit builds, attackers can supply a crafted buffer offset that wraps the bounds check, causing an out-of-bounds read before the buffer and crashing the process.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00382 32nd percentileScored 2026-11-07
Fix No fix listed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
Dvidelabsflatccup to 0.6.4—No fix listedCNA
  • flatcc VendorDvidelabs Affected up to 0.6.4 Fixed in — No fix listed CNA

Remediation

The sources list no fixed version for flatcc.

Written with Claude Haiku 5.5 from the sources below · 2026-10-28

Timeline

  1. 2026-10-26 Threatist record created from CVE-2026-116734
  2. 2026-10-27 CISA SSVC decision points changed
  3. 2026-10-27 Priority changed: MEDIUM → LOW
  4. 2026-10-27 Alias added: GHSA-ch33-r734-vw2g

References

Patch 1

Advisory 1

Other 2

  • TI-2026-61693 Dvidelabs flatcc Duplicate Symbol semantics.c align_order_members assertion CVSS 4.0MEDIUM 6.9
  • TI-2026-61692 Dvidelabs flatcc Struct Analysis semantics.c analyze_struct assertion CVSS 4.0MEDIUM 6.9
  • TI-2026-61691 Dvidelabs flatcc semantics.c fb_clear_parser memory leak CVSS 4.0MEDIUM 6.9
  • TI-2026-80942 flatcc Out-of-Bounds Read via __flatcc_json_parser_number CVSS 4.0MEDIUM 6.3

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences