# CVE-2026-18917: libvirt integer overflow in NodeGetFreePages RPC handler

Source: https://junglewise.ai/threats/cve-2026-18917-libvirt-integer-overflow-in-nodegetfreepages-rpc-handler  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-08-20. Updated: 2026-09-25  
License: CC BY 4.0 with a link back

CVE-2026-18917 · Severity: high · CVSS 7.8 · Published 2026-08-20

libvirt is a virtualization management library used across Linux systems to manage virtual machines and containers. An unprivileged local user can exploit an integer overflow flaw in the NodeGetFreePages RPC handler to corrupt memory in the root libvirt daemon, resulting in denial of service or privilege escalation to root.

Technologies: [Libvirt](https://junglewise.ai/threats/technologies/libvirt). Vendors: [Libvirt](https://junglewise.ai/threats/vendors/libvirt).

## Quick answers

**Is CVE-2026-18917 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-18917 being exploited in the wild.

**How severe is CVE-2026-18917?** High severity, with a CVSS score of 7.8, published 20 August 2026.

**Which products and versions are affected?** Libvirt before 10.0.0-6.24.el9_4.

**Is there a fix for CVE-2026-18917?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-18917 attacked?** It is attacked with local access.

**Am I affected by CVE-2026-18917?** Check whether you run Libvirt at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The vulnerability is an integer overflow in libvirt's NodeGetFreePages RPC handler that allows crafted values to bypass a size check, resulting in undersized memory buffer allocation. This leads to a heap buffer overflow when real NUMA node data overwrites the undersized buffer. An unprivileged local attacker with network access to the libvirt RPC interface can trigger this condition without authentication. Successful exploitation corrupts the root libvirt daemon's memory, enabling denial of service or local privilege escalation. Patches are available via Red Hat Enterprise Linux 9.4 updates (libvirt-10.0.0-6.24.el9_4 and later).

## Affected products

- libvirt libvirt before 10.0.0-6.24.el9_4

## Timeline

- 2026-08-20: disclosed
- 2026-09-17: advisory: Red Hat security advisory RHSA-2026:68509 issued

## References

- [https://access.redhat.com/downloads/content/package-browser/](https://access.redhat.com/downloads/content/package-browser/)
- [https://access.redhat.com/errata/RHSA-2026:68509](https://access.redhat.com/errata/RHSA-2026:68509)

## Related threats

- [libvirt symlink-following flaw in qemuTPMEmulatorPrepareHost](https://junglewise.ai/threats/cve-2026-77159-libvirt-symlink-following-flaw-in-qemutpmemulatorpreparehost)
- [libvirt denial of service via XML parsing resource exhaustion](https://junglewise.ai/threats/cve-2025-12748-libvirt-denial-of-service-via-xml-parsing-resource-exhaustion)