CVE-2026-51539
Description
A flaw was found in libmodbus. This Denial of Service (DoS) vulnerability exists in the receive loop when the software is running on Windows. The issue is caused by improper timeout management during network read operations, which can allow a remote attacker to cause the application to become unresponsive.
Statement
Red Hat distributes libmodbus only as a Linux package, via Fedora and EPEL, and does not ship or support a Windows build. Because Linux's select() semantics do not exhibit the behavior this flaw depends on, libmodbus as built and shipped by Red Hat is not exposed to the attack described.
Mitigation
No mitigation is required to protect the Fedora or EPEL builds of libmodbus, since Red Hat only ships Linux builds, which are not subject to the timeout-bypass behavior this issue depends on.
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Resource Consumption (CPU); DoS: Resource Consumption (Memory); DoS: Resource Consumption (Other); Reduce Performance
This issue can make the product perform more slowly. If an attacker can influence the number of iterations in the loop, then this performance problem might allow a denial of service by consuming more platform resources than intended.
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