USN-8833-1 release notes and known issues

Summary

It was discovered that libvirt did not properly validate newline characters in DNS TXT record values and SRV record attributes in its virtual network driver. A local attacker with permission to define virtual networks could possibly use this issue to inject arbitrary dnsmasq configuration directives, leading to arbitrary command execution as root. (CVE-2026-61477) It was discovered that libvirt did not properly handle errors during XML context parsing. An attacker could possibly use this issue to cause libvirt to crash, resulting in a denial of service. (CVE-2026-61478) He Wei discovered that libvirt had a symlink-following vulnerability in the file ownership change function used for virtual TPM state directories. A local attacker running as the swtpm user could possibly use this issue to cause libvirt to change the ownership of an arbitrary file, leading to privilege escalation. (CVE-2026-63622) It was discovered that libvirt created storage volume images with overly permissive permissions during clone or convert operations. A local attacker could possibly use this issue to read guest disk contents, resulting in information disclosure. (CVE-2026-63623) It was discovered that libvirt had an integer overflow in the NodeGetFreePages RPC handler. A local attacker could possibly use this issue to cause libvirt to crash or execute arbitrary code. (CVE-2026-18917) It was discovered that libvirt had a symlink-following flaw in the virtual TPM emulator setup function. A local attacker with access to the swtpm account could possibly use this issue to cause libvirt to change the ownership of an arbitrary file, leading to privilege escalation. (CVE-2026-77159)

Improvements and security content

• It was discovered that libvirt did not properly validate newline characters in DNS TXT record values and SRV record attributes in its virtual network driver. A local attacker with permission to define virtual networks could possibly use this issue to inject arbitrary dnsmasq configuration directives, leading to arbitrary command execution as root. (CVE-2026-61477) It was discovered that libvirt did not properly handle errors during XML context parsing. An attacker could possibly use this issue to cause libvirt to crash, resulting in a denial of service. (CVE-2026-61478) He Wei discovered that libvirt had a symlink-following vulnerability in the file ownership change function used for virtual TPM state directories. A local attacker running as the swtpm user could possibly use this issue to cause libvirt to change the ownership of an arbitrary file, leading to privilege escalation. (CVE-2026-63622) It was discovered that libvirt created storage volume images with overly permissive permissions during clone or convert operations. A local attacker could possibly use this issue to read guest disk contents, resulting in information disclosure. (CVE-2026-63623) It was discovered that libvirt had an integer overflow in the NodeGetFreePages RPC handler. A local attacker could possibly use this issue to cause libvirt to crash or execute arbitrary code. (CVE-2026-18917) It was discovered that libvirt had a symlink-following flaw in the virtual TPM emulator setup function. A local attacker with access to the swtpm account could possibly use this issue to cause libvirt to change the ownership of an arbitrary file, leading to privilege escalation. (CVE-2026-77159)

Affected products and versions

Recommended action

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Lifecycle connections

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Official publisher evidence