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

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.

Timeline

Scores

EPSS (exploitation in 30 days)

0.18% · top 92% of all CVEs (13 Nov 2026)

CISA SSVC

Exploitation: none · Automatable: no · Technical impact: total

The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.8.

Affected products

• Red Hat · Red Hat Enterprise Linux 10

  • unaffected 0:11.10.0-12.9.el10_2 – < *

• Red Hat · Red Hat Enterprise Linux 10.0 Extended Update Support

  • unaffected 0:10.10.0-8.12.el10_0 – < *

• Red Hat · Red Hat Enterprise Linux 7 Extended Lifecycle Support

  • unaffected 0:4.5.0-36.el7_9.7 – < *

• Red Hat · Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support

  • unaffected 8040020260916092751.522a0ee4 – < *

• Red Hat · Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On

  • unaffected 8040020260916092751.522a0ee4 – < *

• Red Hat · Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support

  • unaffected 8060020260910092451.ad008a3a – < *

• Red Hat · Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On

  • unaffected 8060020260910092451.ad008a3a – < *

• Red Hat · Red Hat Enterprise Linux 8.8 Telecommunications Update Service

  • unaffected 8080020260910092120.63b34585 – < *

• Red Hat · Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions

  • unaffected 8080020260910092120.63b34585 – < *

• Red Hat · Red Hat Enterprise Linux 9

  • unaffected 0:11.10.0-12.7.el9_8 – < *

• Red Hat · Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions

  • unaffected 0:9.0.0-10.17.el9_2 – < *

• Red Hat · Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions

  • unaffected 0:10.0.0-6.24.el9_4 – < *

• Red Hat · Red Hat Enterprise Linux 9.6 Extended Update Support

  • unaffected 0:10.10.0-7.19.el9_6 – < *

• Red Hat · Red Hat Enterprise Linux 6

  All versions: unaffected

• Red Hat · Red Hat Enterprise Linux 8

  All versions: affected

• Red Hat · Red Hat Enterprise Linux for NVIDIA 26

  All versions: unknown

What to do

Workaround: Restrict access to the libvirt read-only Unix socket to limit which local users can reach the vulnerable RPC handler. In /etc/libvirt/libvirtd.conf, set unix_sock_ro_perms to "0770" (or "0700") and configure unix_sock_group to a group containing only trusted users. Alternatively, enable polkit authentication for the read-only socket by setting auth_unix_ro = "polkit", which requires callers to be authorized before any RPC dispatch occurs. After changing the configuration, restart the libvirtd service. Note: restricting socket access may prevent unprivileged monitoring tools or read-only management clients from connecting.

Sources

The same CVE in the primary databases and aggregators, to check against.

• CVE.org record (opens in a new tab)
• CVE List JSON (GitHub) (opens in a new tab)
• NVD (opens in a new tab)
• FIRST EPSS (opens in a new tab)
• EUVD EUVD-2026-63239 (opens in a new tab)
• OSV.dev (opens in a new tab)
• GitHub Advisories (opens in a new tab)
• CIRCL Vulnerability-Lookup (opens in a new tab)

Badge for a README or a ticket

[![CVE-2026-18917](https://cveledger.app/badge/CVE-2026-18917.svg)](https://cveledger.app/cve/CVE-2026-18917)

Record last updated 4 Nov 2026, 22:11 UTC.