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Linux KernelOperating system · Linux

CVE-2025-68340

MEDIUM · 5.5 CVSS v3.1 Published 2025-12-23
Fix available
A fix is available. Upgrade to 5.15.199 / 6.1.162 or later.
See remediation →
57/100
Remediation priority · Elevated
Zero-click Patch available

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
In the Linux kernel, the following vulnerability has been resolved: team: Move team device type change at the end of team_port_add Attempting to add a port device that is already up will expectedly fail, but not before modifying the team device header_ops. In the case of the syzbot reproducer the gre0 device is already in state UP when it attempts to add it as a port device of team0, this fails but before that header_ops->create of team0 is changed from eth_header to ipgre_header in the call to team_dev_type_check_change. Later when we end up in ipgre_header() struct ip_tunnel* points to nonsense as the private data of the device still holds a struct team. Example sequence of iproute2 commands to reproduce the hang/BUG(): ip link add dev team0 type team ip link add dev gre0 type gre ip link set dev gre0 up ip link set dev gre0 master team0 ip link set dev team0 up ping -I team0 1.1.1.1 Move team_dev_type_check_change down where all other checks have passed as it changes the dev type with no way to restore it in case one of the checks that follow it fail. Also make sure to preserve the origial mtu assignment: - If port_dev is not the same type as dev, dev takes mtu from port_dev - If port_dev is the same type as dev, port_dev takes mtu from dev This is done by adding a conditional before the call to dev_set_mtu to prevent it from assigning port_dev->mtu = dev->mtu and instead letting team_dev_type_check_change assign dev->mtu = port_dev->mtu. The conditional is needed because the patch moves the call to team_dev_type_check_change past dev_set_mtu. Testing: - team device driver in-tree selftests - Add/remove various devices as slaves of team device - syzbot

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis

A detailed technical summary for this CVE is being prepared.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Linux KernelOperating system
Affected:>= 3.7, < 5.15.199>= 5.16, < 6.1.162>= 6.2, < 6.6.123>= 6.7, < 6.12.61>= 6.13, < 6.17.11= 6.18

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 5.15.199 / 6.1.162 / 6.6.123 or later
Fixed in 5.15.1996.1.1626.6.123
Vendor patch git.kernel.org →
Recommended fix High confidence

5.15.199, 6.1.162, 6.6.123, or 6.12.61 (depending on which kernel branch you are on)

  1. Upgrade the Linux kernel to version 5.15.199 or later if currently running 5.15.x
  2. Upgrade the Linux kernel to version 6.1.162 or later if currently running 6.1.x
  3. Upgrade the Linux kernel to version 6.6.123 or later if currently running 6.6.x
  4. Upgrade the Linux kernel to version 6.12.61 or later if currently running 6.7.x through 6.12.x
  5. After kernel upgrade, reboot the system to load the fixed kernel
Caveat Kernel upgrades may require rebuilding out-of-tree kernel modules; ensure compatibility with existing system configuration

Generated from the published advisory — verify against the referenced sources before acting.

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2025-68340 in production — separate from our analysis above.

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