net: udp_tunnel: prevent double queueing in udp_tunnel_nic_device_sync (CVE-2026-72405) | HOL Guard CVE

High · CVSS 7.8CVE-2026-72405

net: udp_tunnel: prevent double queueing in udp_tunnel_nic_device_sync

Answer in brief

CVE-2026-72405 records a High severity (CVSS 7.8) vulnerability in net: udp_tunnel: prevent double queueing in udp_tunnel_nic_device_sync. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Aug 15, 2026Updated Aug 17, 2026Source checked Sep 29, 2026First seen by HOL Aug 15, 2026Material review Aug 17, 2026

Upstream Advisory

Key facts

Risk: High · CVSS 7.8
Exploitation: Not marked as known exploited
Affected software: 2 mapped packages or products
Fix availability: Available

Why this deserves its current priority

CVSS is 7.8. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
Linux/Linuxgeneric	>=cc4e3835eff474aa274d6e1d18f69d9d296d3b76 <cee6688e5731c0591643521716d1a1a5c1a98bf8 \|\| >=cc4e3835eff474aa274d6e1d18f69d9d296d3b76 <9075efb9b2c1d9d7a8285c937b64aa93ca0c41b7 \|\| >=cc4e3835eff474aa274d6e1d18f69d9d296d3b76 <54292b167466cdf42176b7b6f01da66c184deb12 \|\| >=cc4e3835eff474aa274d6e1d18f69d9d296d3b76 <ecf69d4b43370c587e48d4d70289dbdb7e039d4d	cee6688e5731c0591643521716d1a1a5c1a98bf8, 9075efb9b2c1d9d7a8285c937b64aa93ca0c41b7, 54292b167466cdf42176b7b6f01da66c184deb12, ecf69d4b43370c587e48d4d70289dbdb7e039d4d
Linux/Linuxgeneric	5.9	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for Linux/Linux, Linux/Linux.
Review the reported fix. Update Linux/Linux to cee6688e5731c0591643521716d1a1a5c1a98bf8 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Aug 15, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Aug 17, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Aug 15, 2026

Sources and claim methodology

Upstream source description

In the Linux kernel, the following vulnerability has been resolved: net: udp_tunnel: prevent double queueing in udp_tunnel_nic_device_sync Yue Sun reported a use-after-free and debugobjects warning in udp_tunnel_nic_device_sync_work() during concurrent device operations. The workqueue core clears the internal pending bit before invoking the worker. At that point, a concurrent thread can queue the work again. When the already running worker eventually clears the work_pending flag to 0, it mistakenly clears the flag for the newly queued instance. udp_tunnel_nic_unregister() then observes work_pending as 0 and frees the structure while the second work item is still active in the queue, leading to UAF. Fix this by returning early in udp_tunnel_nic_device_sync() if work_pending is already set, preventing redundant work queueing.

Quoted source text, attributed separately from HOL analysis.