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VulnerabilityPublished Updated

CVE-2026-63917: Linux kernel · ip6: vti: Use ip6_tnl.net in vti6_changelink().

Affects Linux kernelSource CVE Database V5

0

Not known to be exploited · CVSS 8.8 High · fixed in fc32be9ac2788524c6b24efd681cce7a6e731a92 : patch Linux kernel soon.

Data as of 26 Oct 2026, 17:16 UTC

CVSS 3.1 base score
8.8High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.1% chance of exploitation in 30 days – higher than 6% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CISA SSVC
Exploitation
No evidence of active exploitation and no public proof of concept
Automatable
Attackers cannot reliably automate steps 1–4 of the kill chain
Technical impact
Total control over the software or total information disclosure

CISA SSVC assessment, 2026-10-16.

Patch
Available – fixed in fc32be9ac2788524c6b24efd681cce7a6e731a92, f5c68875e25f331e497ddfbe81e2d8163a87f136, f1e89a943ee574d0f2f16246eb3f2d7330fdeb03 +5
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 19 Jul 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: 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 26 Oct 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
LinuxLinuxAffected
  • ≥ 61220ab349485d911083d0b7990ccd3db6c63297, < fc32be9ac2788524c6b24efd681cce7a6e731a92
Fixed in
  • fc32be9ac2788524c6b24efd681cce7a6e731a92
LinuxLinuxAffected
  • ≥ 61220ab349485d911083d0b7990ccd3db6c63297, < f5c68875e25f331e497ddfbe81e2d8163a87f136
Fixed in
  • f5c68875e25f331e497ddfbe81e2d8163a87f136
LinuxLinuxAffected
  • ≥ 61220ab349485d911083d0b7990ccd3db6c63297, < f1e89a943ee574d0f2f16246eb3f2d7330fdeb03
Fixed in
  • f1e89a943ee574d0f2f16246eb3f2d7330fdeb03
LinuxLinuxAffected
  • ≥ 61220ab349485d911083d0b7990ccd3db6c63297, < ee1778ba0f5cb53be771f97017d01eb356c797bf
Fixed in
  • ee1778ba0f5cb53be771f97017d01eb356c797bf
LinuxLinuxAffected
  • ≥ 61220ab349485d911083d0b7990ccd3db6c63297, < d9c5eecdb3c740e65038651db7c686b10d76d1bc
Fixed in
  • d9c5eecdb3c740e65038651db7c686b10d76d1bc
LinuxLinuxAffected
  • ≥ 61220ab349485d911083d0b7990ccd3db6c63297, < 225b467e3b631f38be22e4b38062a1fed02fdd21
Fixed in
  • 225b467e3b631f38be22e4b38062a1fed02fdd21

Description

In the Linux kernel, the following vulnerability has been resolved: ip6: vti: Use ip6_tnl.net in vti6_changelink(). ip netns add ns1 ip netns add ns2 ip -n ns1 link add vti6_test type vti6 remote ::1 local ::2 key 7 ip -n ns1 link set vti6_test netns ns2 ip -n ns2 link set vti6_test type vti6 remote ::3 local ::4 key 9 ip netns del ns2 ip netns del ns1 [ 132.495484] ------------[ cut here ]------------ [ 132.497609] kernel BUG at net/core/dev.c:12376! Commit 61220ab34948 ("vti6: Enable namespace changing") dropped NETIF_F_NETNS_LOCAL from vti6 devices. A vti6 tunnel can then move through IFLA_NET_NS_FD. After the move dev_net(dev) points at the new netns while t->net stays at the creation netns. vti6_changelink() and vti6_update() still use dev_net(dev) and dev_net(t->dev). They unlink from one per netns hash and relink into another. The creation netns is left with a stale entry. cleanup_net() of that netns later walks freed memory. Reachable from an unprivileged user namespace (unshare --user --map-root-user --net). Cross tenant scope on container hosts.

References

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