Vulnerability · Published Oct 23, 2026 · Assigned by VulnCheck

CVE-2026-115723Snap7 through 1.4.3 Out-of-Bounds Write via BRecv and CheckAsBRecvCompletion

High 7.4

In plain English

A high-severity out-of-bounds write in snap7 from davenardella. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 36% of all known vulnerabilities).

Severity (CVSS 3.1)7.4High

Exploit odds (30 days)0.4%top 63.7% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

Snap7 through 1.4.3 contains an out-of-bounds write vulnerability in the passive partner that allows a malicious active partner to overflow application buffers by declaring an unvalidated BSend total length. Attackers connecting from the configured peer address can declare up to 65535 bytes and send a short fragment, causing BRecv to memcpy past the buffer and crash or corrupt SCADA, HMI or gateway processes.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Ubuntu:26.04:LTS	snap7	no fix listed	UBUNTU-CVE-2026-115723
Ubuntu:26.10	snap7	no fix listed	UBUNTU-CVE-2026-115723

Affected products (as reported)

Vendor	Product	Versions
davenardella	snap7	0 – through 1.4.3

Weakness: CWE-787 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:H

References

https://github.com/davenardella/snap7/pull/41 issue-tracking, patch
https://github.com/davenardella/snap7/blob/30f37da3114024a71ba93f7fd855c680b97a406f/src/core/s7_partner.cpp#L1126-L1166 technical-description
https://github.com/davenardella/snap7/blob/30f37da3114024a71ba93f7fd855c680b97a406f/src/core/s7_partner.cpp#L850-L867 technical-description
VulnCheck Advisory: Snap7 through 1.4.3 Out-of-Bounds Write via BRecv and CheckAsBRecvCompletion third-party-advisory