CVE-2026-71263 json
FreeModbus LINUXTCP Port Off-by-One Global Buffer Overflow in xMBPortTCPPool()
published 2026-08-05 3 mo ago modified 2026-10-24 15 d ago also EUVD-2026-53348
- cvss
- 9.1
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.5%
- EPSS 0.5% chance of exploitation in 30 days, percentile 43%
- public exploits
- 0
- none known
Summary
The LINUXTCP port of FreeModbus contains an off-by-one bounds check in xMBPortTCPPool (demo/LINUXTCP/port/porttcp.c). The check uses a strict greater-than comparison instead of greater-than-or-equal against the 263-byte MB_TCP_BUF_SIZE limit.
CISA SSVC
- Exploitation
- none
- Automatable
- yes
- Technical impact
- partial
- Assessed
- 3 mo ago
Exploit prediction
0.50% chance of exploitation in the next 30 days, higher than 43% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 9.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H |
Affected products
- cwalter-at FreeModbus
Classification
- Weakness
-
- CWE-787 Out-of-bounds Write
References
-
github.com
/cwalter-at/freemodbus
third-party-advisory
-
github.com
/cwalter-at/freemodbus/blob/master/demo/LINUXTCP/port/porttcp.c
third-party-advisory
Sources
- CVE List CVE-2026-71263
- NVD CVE-2026-71263
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.