CVE-2026-18917: libvirt Integer Overflow or Wraparound

Vulnerability summary

CVE-2026-18917 is a high (CVSS 7.8) Integer Overflow or Wraparound vulnerability in libvirt. EPSS estimates a 0.18% chance of exploitation in the next 30 days, higher than 7.2% of scored vulnerabilities.

Timeline

1. 20-08-2026
   PublishedVulnerability first disclosed.
2. 05-10-2026
   Last modifiedVulnerability information updated.

Description

A flaw was found in libvirt. An unprivileged local user could exploit an integer overflow vulnerability in the NodeGetFreePages RPC handler. This flaw allows crafted values to bypass a size check, leading to an undersized memory buffer. Subsequently, real NUMA node data can overwrite this buffer. This heap buffer overflow can corrupt the root libvirt daemon's memory, potentially leading to a denial of service or local privilege escalation.

• CWE-190Integer Overflow or WraparoundThe product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.