What’s Vulnerable › Vulnerabilities

CVE-2026-111280: snap7 through 1.4.3 Out-of-Bounds Write via TSnap7MicroClient::opReadArea

• Severity: high (CVSS 7.4 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-15 · updated 2026-10-29
• Weakness: CWE-787

Description

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.

Affected products

• davenardella snap7: through 1.4.3

References

• https://github.com/davenardella/snap7
• https://github.com/davenardella/snap7/blob/30f37da3114024a71ba93f7fd855c680b97a406f/src/core/s7_micro_client.cpp#L136-L150
• https://github.com/davenardella/snap7/issues/31
• https://www.vulncheck.com/advisories/snap7-through-1.4.3-out-of-bounds-write-via-tsnap7microclient-opreadarea
• https://github.com/davenardella/snap7/issues/31

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