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VulnerabilityPublished

CVE-2026-100395: lxc · Link Following

Affects lxcSource CVE Database V5

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Not known to be exploited · CVSS 6.8 Medium.

Data as of 5 Nov 2026, 22:33 UTC

CVSS 4.0 base score
6.8Medium
How severe the flaw is on the 0–10 CVSS scale.

Thin evidence

One scorer or none
CVSS scores by source
CNA (GitHub_M)CVSS 4.06.8
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 5 Nov 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 5 Nov 2026.

What to do

Affected software

ProductAffectedFixed in
lxclxcAffected
  • <=7.0.0
Fixed in–

AI-suggested

As a mitigation, use the LXC_CLONE_KEEPNAME flag during cloning to avoid the hostname update and prevent the vulnerable write operation. Avoid cloning containers from untrusted or attacker-controlled root filesystems. Since unprivileged cloning and independent cloning implementations are not affected, prefer those when possible.

Description

CVE-2026-100395 is a vulnerability in LXC version 7.0.0 and earlier where the lxc-copy tool and the liblxc clone() API can follow attacker-controlled symbolic links when updating /etc/hostname in a copied container root filesystem. This can lead to a privileged process overwriting files outside the intended container root filesystem if the source rootfs is attacker-controlled or less trusted. The issue arises because the clone operation preserves symlinks before updating the hostname, allowing a symlink to point outside the destination rootfs. Unprivileged users and independent cloning implementations are not affected. Using the LXC_CLONE_KEEPNAME flag avoids the hostname update and mitigates the issue.

References

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