CVE-2026-115723
Snap7 through 1.4.3 Out-of-Bounds Write via BRecv and CheckAsBRecvCompletion
- State
- Published
- Severity
- 8.3 High
- Published
- Oct 23, 2026
- Updated
- Oct 23, 2026
- Reserved
- Oct 23, 2026
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 8.3 High | 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 | VulnCheck |
| 3.1 | 7.4 High | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:H | VulnCheck |
Weaknesses
- CWE-787 Out-of-bounds Write
Affected Products
| Product | Versions |
|---|---|
snap7davenardella |
|
References
- https://github.com/davenardella/snap7/pull/41issue-trackingpatch
- https://github.com/davenardella/snap7/blob/30f37da3114024a71ba93f7fd855c680b97a406f/src/core/s7_partner.cpp#L1126-L1166technical-description
- https://github.com/davenardella/snap7/blob/30f37da3114024a71ba93f7fd855c680b97a406f/src/core/s7_partner.cpp#L850-L867technical-description
- VulnCheck Advisory: Snap7 through 1.4.3 Out-of-Bounds Write via BRecv and CheckAsBRecvCompletionthird-party-advisory
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