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

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-08-20 · updated 2026-10-27
Weakness: CWE-190

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.

Affected products

Red Hat Enterprise Linux 10: all versions — fixed in 0:11.10.0-12.9.el10_2
Red Hat Enterprise Linux 10.0 Extended Update Support: all versions — fixed in 0:10.10.0-8.12.el10_0
Red Hat Enterprise Linux 7 Extended Lifecycle Support: all versions — fixed in 0:4.5.0-36.el7_9.7
Red Hat Enterprise Linux 8: all versions
Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support: all versions — fixed in 8040020260916092751.522a0ee4
Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On: all versions — fixed in 8040020260916092751.522a0ee4
Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support: all versions — fixed in 8060020260910092451.ad008a3a
Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On: all versions — fixed in 8060020260910092451.ad008a3a
Red Hat Enterprise Linux 8.8 Telecommunications Update Service: all versions — fixed in 8080020260910092120.63b34585
Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions: all versions — fixed in 8080020260910092120.63b34585
Red Hat Enterprise Linux 9: all versions — fixed in 0:11.10.0-12.7.el9_8
Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions: all versions — fixed in 0:9.0.0-10.17.el9_2
Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions: all versions — fixed in 0:10.0.0-6.24.el9_4
Red Hat Enterprise Linux 9.6 Extended Update Support: all versions — fixed in 0:10.10.0-7.19.el9_6

How to fix

Upgrade to a fixed version: Red Hat Enterprise Linux 10 0:11.10.0-12.9.el10_2; Red Hat Enterprise Linux 10.0 Extended Update Support 0:10.10.0-8.12.el10_0; Red Hat Enterprise Linux 7 Extended Lifecycle Support 0:4.5.0-36.el7_9.7; Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support 8040020260916092751.522a0ee4; Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On 8040020260916092751.522a0ee4; Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support 8060020260910092451.ad008a3a; Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On 8060020260910092451.ad008a3a; Red Hat Enterprise Linux 8.8 Telecommunications Update Service 8080020260910092120.63b34585; Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions 8080020260910092120.63b34585; Red Hat Enterprise Linux 9 0:11.10.0-12.7.el9_8; Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions 0:9.0.0-10.17.el9_2; Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions 0:10.0.0-6.24.el9_4. Check the vendor advisory for mitigations.

References

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