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8.3

snap7 client may crash from malicious PLC data

CVE-2026-111280 · published 23 days ago
Summary

The snap7 library (versions up to 1.4.3) can be forced to write beyond its memory limits when a programmable logic controller (PLC) sends specially crafted data. This can cause the software that talks to the PLC—such as SCADA, HMI or gateway applications—to stop working or behave unpredictably. Upgrade snap7 to a newer safe version or apply the vendor's fix, and ensure any external PLC connections are trusted.

What to do

The CVE record does not list a fixed version. Check the vendor's site or the advisory links below - a fix may already be released.

Affected software
Ecosystem VendorProductAffected versions
– davenardella snap7 <= 1.4.3
Ubuntu:26.10 canonical snap7 All versions
Original advisory text
snap7 through 1.4.3 Out-of-Bounds Write via TSnap7MicroClient::opReadArea
snap7 through 1.4.3 contains an out-of-bounds write vulnerability in TSnap7MicroClient::opReadArea() that allows malicious S7 peers to overflow client buffers via an unchecked DataLength field. Rogue or impersonated PLCs can return crafted ReadVar responses causing memcpy of up to 65535 bytes into caller buffers, crashing SCADA, HMI, or gateway processes and corrupting memory.
References
Fix within
Internet-facing 60 days
Internal At next upgrade
  • Not known to be exploited
  • Needs hands-on effort to exploit
  • Gives an attacker partial control
Severity
8.3 High
Exploitation
<1% chance of attack within 30 days
Type
CWE-787Out-of-bounds Write
Timeline
Published15 Oct 2026
Updated7 Nov 2026
First seen15 Oct 2026
Sources
CVE-2026-111280 · NVD
CVE-2026-111280 · MITRE
UBUNTU-CVE-2026-111280 · OSV
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