CVE-2026-115723

high

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.

References

https://www.vulncheck.com/advisories/snap7-through-1.4.3-out-of-bounds-write-via-brecv-and-checkasbrecvcompletion

https://github.com/davenardella/snap7/pull/41

https://github.com/davenardella/snap7/blob/30f37da3114024a71ba93f7fd855c680b97a406f/src/core/s7_partner.cpp#L850-L867

https://github.com/davenardella/snap7/blob/30f37da3114024a71ba93f7fd855c680b97a406f/src/core/s7_partner.cpp#L1126-L1166

https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-108711

Details

Source: Mitre, NVD

Published: 2026-10-23

Updated: 2026-10-23

Risk Information

CVSS v2

Base Score: 7.1

Vector: CVSS2#AV:N/AC:H/Au:N/C:N/I:C/A:C

Severity: High

CVSS v3

Base Score: 7.4

Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:H

Severity: High

CVSS v4

Base Score: 8.3

Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N

Severity: High

EPSS

EPSS: 0.00418