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TI-2026-80942 Aliases CVE-2026-116733GHSA-ffg2-pv59-mvp5

flatcc Out-of-Bounds Read via __flatcc_json_parser_number

Priority MEDIUM 61CWE-125Published · 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 out-of-bounds read (CWE-125) in __flatcc_json_parser_number that lets attackers read past the input buffer via numbers ending in a decimal point. An attacker who supplies untrusted JSON ending right after a decimal point can crash applications using generated parsers when the buffer ends at an unmapped page. CVSS 4.0 scores it 6.3 (MEDIUM), and CISA SSVC rates exploitation as PoC, not automatable, with partial technical impact.

Written with Claude Haiku 5.5 from the sources below · 2026-11-02

Description from the CNA

flatcc through 0.6.4 contains an out-of-bounds read vulnerability in __flatcc_json_parser_number that allows attackers to read past the input buffer via numbers ending in a decimal point. Attackers can supply untrusted JSON ending immediately after a decimal point to generated parsers, crashing applications when the buffer ends at an unmapped page.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00421 36th 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
Poc
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

No fix is listed for flatcc through 0.6.4. Restrict generated parsers to trusted JSON input until a fixed version is available.

Written with Claude Haiku 5.5 from the sources below · 2026-11-02

Timeline

  1. 2026-10-26 Threatist record created from CVE-2026-116733
  2. 2026-10-27 Alias added: GHSA-ffg2-pv59-mvp5
  3. 2026-10-27 Priority changed: MEDIUM → LOW
  4. 2026-11-02 CISA SSVC decision points changed
  5. 2026-11-02 Priority changed: LOW → MEDIUM

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-2026-80943 Integer overflow in flatcc verifier causes out-of-bounds read CVSS 4.0MEDIUM 6.3

Sources

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