---
title: "CVE-2026-115723: Snap7 - Buffer Overflow"
description: "Snap7 through 1.4.3 contains a buffer overflow caused by unvalidated BSend total length in the passive partner, letting malicious active partners overflow application buffers, exploit requires attacker to connect from configured peer address."
url: https://panop.io/threat-heartbeat/CVE-2026-115723/
---

# CVE-2026-115723 Snap7 - Buffer Overflow

Snap7 through 1.4.3 contains a buffer overflow caused by unvalidated BSend total length in the passive partner, letting malicious active partners overflow application buffers, exploit requires attacker to connect from configured peer address.

CVSS base score 7.4 /10

High

CISA KEV

Not listed

Public exploit

None known

EPSS

0.62% chance of exploitation in 30 days

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-115723)

## Details

Type

Buffer Overflow

Impact

Denial Of Service, Data Tampering

CVSS vector

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

Published

23 October 2026

Updated

25 October 2026

Weakness

[CWE-787](https://cwe.mitre.org/data/definitions/787.html)

## Vendor fix

Update to the latest version beyond 1.4.3.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

## References

- [https://nvd.nist.gov/vuln/detail/CVE-2026-115723](https://nvd.nist.gov/vuln/detail/CVE-2026-115723)
- [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#L850-L867)
- [https://github.com/davenardella/snap7/pull/41](https://github.com/davenardella/snap7/pull/41)
- [https://www.vulncheck.com/advisories/snap7-through-1.4.3-out-of-bounds-write-via-brecv-and-checkasbrecvcompletion](https://www.vulncheck.com/advisories/snap7-through-1.4.3-out-of-bounds-write-via-brecv-and-checkasbrecvcompletion)
- [https://github.com/davenardella/snap7/blob/30f37da3114024a71ba93f7fd855c680b97a406f/src/core/s7\_partner.cpp#L1126-L1166](https://github.com/davenardella/snap7/blob/30f37da3114024a71ba93f7fd855c680b97a406f/src/core/s7_partner.cpp#L1126-L1166)

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## What this record can't tell you

- Whether you run the affected software, and where
- Whether an attacker can actually reach and exploit it
- The misconfigurations that never get a CVE number
- What it would cost the business, ranked into what to fix first

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