High [CVE-2026-18917] Libvirt: integer overflow in nodegetfreepages rpc handler leading to heap buffer overflow
This high-severity Red Hat Linux advisory covers CVE-2026-18917 affecting Red Hat Enterprise Linux 10.0 Extended Update Support, Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support, Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On.
Aggregated and source-linked by VulniPulse. Data sources, validation and limitations.
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Summary
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. Red Hat severity: Important — CVSS 7.8 (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H).
Weakness: CWE-190.
Affected Red Hat products: Red Hat Enterprise Linux 10.0 Extended Update Support; Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support; Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On; Red Hat Enterprise Linux 8.8 Telecommunications Update Service; Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions; Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions; Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions; Red Hat Enterprise Linux 9.6 Extended Update Support; Red Hat Enterprise Linux 10; Red Hat Enterprise Linux 7; Red Hat Enterprise Linux 8; Red Hat Enterprise Linux 9; Red Hat Enterprise Linux for NVIDIA 26.
Red Hat lists Red Hat Enterprise Linux 6 as not affected. Will not fix / out of support: Red Hat Enterprise Linux for NVIDIA 26.
Affected versions
No affected-version range was extracted from the source record. The vendor advisory is authoritative — check it before change work.
Official advisory · high-confidence parse· fetched 16 days ago·verify at source
- libvirt-0:10.10.0-8.12.el10_0
- virt:rhel-8060020260910092451.ad008a3a
- virt:rhel-8080020260910092120.63b34585
- libvirt-0:9.0.0-10.17.el9_2
- libvirt-0:10.0.0-6.24.el9_4
- libvirt-0:10.10.0-7.19.el9_6
- RHSA-2026:68510
- RHSA-2026:68594
- RHSA-2026:68513
- RHSA-2026:68514
- RHSA-2026:68509
- RHSA-2026:68511
Official advisory · high-confidence parse· fetched 16 days ago·verify at source
Mitigation checklist
- 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.
Official advisory · high-confidence parse· fetched 16 days ago·verify at source
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