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2 vulnerabilities found for lxc by lxc
CVE-2026-100395 (GCVE-0-2026-100395)
Vulnerability from cvelistv5 – Published: 2026-11-05 21:45 – Updated: 2026-11-09 17:41
VLAI
EPSS
VEX
Title
LXC: lxc-copy host-context hostname update follows symlink
Summary
LXC is a userspace interface for the Linux kernel containment features used to create and manage system containers. In LXC 7.0.0 and earlier, lxc-copy and the public liblxc clone() API can follow attacker-controlled symbolic links while updating /etc/hostname in a copied container root filesystem. The affected surfaces are lxc-copy and liblxc's public lxc_container::clone() API. The privileged cloning process must run as root. The source rootfs must be attacker-controlled or less trusted. A symlink can be placed at etc/hostname or in an intermediate component. The clone operation preserves the symlink before updating the hostname. The vulnerable write truncates and overwrites an existing file outside the destination rootfs. When root clones an untrusted container without LXC_CLONE_KEEPNAME, the copied symlink can resolve outside the destination rootfs and cause the privileged process to overwrite an existing host file with the destination container name. Unprivileged use and managers with independent cloning implementations are not affected. LXC_CLONE_KEEPNAME avoids the hostname update and therefore the affected write.
Severity
SSVC
Exploitation: none
Automatable: no
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-11-09 17:36 UTC
CWE
Assigner
GitHub_M
CNA
References
3 references
| URL | Tags |
|---|---|
| https://github.com/lxc/lxc/security/advisories/GH… | x_refsource_CONFIRM |
| https://github.com/lxc/lxc/commit/6424a91a55efc54… | x_refsource_MISC |
| https://github.com/lxc/lxc/commit/fa12709a79c2b63… | x_refsource_MISC |
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CVE-2026-39402 (GCVE-0-2026-39402)
Vulnerability from cvelistv5 – Published: 2026-05-05 20:45 – Updated: 2026-05-06 14:57
VLAI
EPSS
VEX
Title
lxc lxc-user-nic insufficient ownership validation allows cross-tenant OVS port deletion
Summary
lxc is a Linux container runtime. In the setuid helper lxc-user-nic, the delete path contains a logic flaw in the find_line() function that allows an unprivileged user to delete OVS-attached network interfaces belonging to other users. When lxc-user-nic delete scans its NIC database to authorize a deletion request, the interface name comparison can set the authorization flag based on a name match alone, even when the ownership, type, and link fields in that database entry belong to a different user. The vulnerable check sits after the goto next label handling, meaning it is reachable on lines where earlier ownership checks failed or were skipped. Because nothing downstream of this authorization signal re-verifies that the matched database line actually belongs to the caller, an unprivileged attacker with a valid lxc-usernet policy entry can trigger deletion of another user's OVS port on the same bridge.
This is limited to multi-tenant environments using lxc-user-nic with OpenVSwitch bridges. The impact is denial of service - one tenant can repeatedly disconnect networking from containers run by another tenant on shared infrastructure. This is patched in version 7.0.0.
Severity
SSVC
Exploitation: poc
Automatable: no
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-05-06 14:57 UTC
CWE
- CWE-863 - Incorrect Authorization
Assigner
GitHub_M
CNA
References
1 reference
| URL | Tags |
|---|---|
| https://github.com/lxc/lxc/security/advisories/GH… | x_refsource_CONFIRM |
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