CVE-2026-23393

Aliases:UBUNTU-CVE-2026-23393DEBIAN-CVE-2026-23393
Advisory lineage Upstream: 0 Downstream: 110
Analyzed
Published: 25 Mar 2026, 10:33
Last modified:05 Aug 2026, 12:21

Vulnerability Summary

Overall Risk (default)
medium
31/100
CVSS Score
7.8 HIGH
v3.1 (cve.org)
EPSS Score
0.1% LOW
0% probability 0.00%
KEV
Not listed
Ransomware
No reports
Public exploits
None found
Dark Web
Not detected

Timeline

25 Mar 2026, 10:33
Published
Vulnerability first disclosed
05 Aug 2026, 12:21
Last Modified
Vulnerability information updated

Description

In the Linux kernel, the following vulnerability has been resolved: bridge: cfm: Fix race condition in peer_mep deletion When a peer MEP is being deleted, cancel_delayed_work_sync() is called on ccm_rx_dwork before freeing. However, br_cfm_frame_rx() runs in softirq context under rcu_read_lock (without RTNL) and can re-schedule ccm_rx_dwork via ccm_rx_timer_start() between cancel_delayed_work_sync() returning and kfree_rcu() being called. The following is a simple race scenario: cpu0 cpu1 mep_delete_implementation() cancel_delayed_work_sync(ccm_rx_dwork); br_cfm_frame_rx() // peer_mep still in hlist if (peer_mep->ccm_defect) ccm_rx_timer_start() queue_delayed_work(ccm_rx_dwork) hlist_del_rcu(&peer_mep->head); kfree_rcu(peer_mep, rcu); ccm_rx_work_expired() // on freed peer_mep To prevent this, cancel_delayed_work_sync() is replaced with disable_delayed_work_sync() in both peer MEP deletion paths, so that subsequent queue_delayed_work() calls from br_cfm_frame_rx() are silently rejected. The cc_peer_disable() helper retains cancel_delayed_work_sync() because it is also used for the CC enable/disable toggle path where the work must remain re-schedulable.

CVSS Metrics

  • v4.0•HIGH•Score: 7.3CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
  • v3.1•HIGH•Score: 7.8CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS Trends

Current EPSS score: 0.10%• Percentile: 1%

Techniques & Countermeasures

  • CWE-362•Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

    The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.

Affected Systems

  • debian•linux

    all | < 6.12.85-1 | < 6.19.10-1

  • ubuntu•linux

    all | all | all

  • ubuntu•linux-allwinner-5.19

    all

  • ubuntu•linux-aws

    all | all | all

  • ubuntu•linux-aws-5.0

    all

  • ubuntu•linux-aws-5.11

    all

  • ubuntu•linux-aws-5.13

    all

  • ubuntu•linux-aws-5.15

    all

  • ubuntu•linux-aws-5.19

    all

  • ubuntu•linux-aws-5.3

    all

  • ubuntu•linux-aws-5.8

    all

  • ubuntu•linux-aws-6.14

    all

  • ubuntu•linux-aws-6.17

    all

  • ubuntu•linux-aws-6.2

    all

  • ubuntu•linux-aws-6.5

    all

  • ubuntu•linux-aws-6.8

    all

  • ubuntu•linux-aws-fips

    all

  • ubuntu•linux-azure

    all | all | all | all

  • ubuntu•linux-azure-5.11

    all

  • ubuntu•linux-azure-5.13

    all

  • ubuntu•linux-azure-5.15

    all

  • ubuntu•linux-azure-5.19

    all

  • ubuntu•linux-azure-5.3

    all

  • ubuntu•linux-azure-5.8

    all

  • ubuntu•linux-azure-6.11

    all

  • ubuntu•linux-azure-6.14

    all

  • ubuntu•linux-azure-6.17

    all

  • ubuntu•linux-azure-6.2

    all

  • ubuntu•linux-azure-6.5

    all

  • ubuntu•linux-azure-6.8

    all

  • ubuntu•linux-azure-edge

    all

  • ubuntu•linux-azure-fde

    all | all | all | all

  • ubuntu•linux-azure-fde-5.19

    all

  • ubuntu•linux-azure-fde-6.14

    all

  • ubuntu•linux-azure-fde-6.17

    all

  • ubuntu•linux-azure-fde-6.2

    all

  • ubuntu•linux-azure-fde-6.8

    all

  • ubuntu•linux-azure-fips

    all

  • ubuntu•linux-azure-nvidia

    all

  • ubuntu•linux-azure-nvidia-6.14

    all

  • ubuntu•linux-bluefield

    all

  • ubuntu•linux-fips

    all

  • ubuntu•linux-gcp

    all | all | all | all

  • ubuntu•linux-gcp-5.11

    all

  • ubuntu•linux-gcp-5.13

    all

  • ubuntu•linux-gcp-5.15

    all

  • ubuntu•linux-gcp-5.19

    all

  • ubuntu•linux-gcp-5.3

    all

  • ubuntu•linux-gcp-5.8

    all

  • ubuntu•linux-gcp-6.11

    all

Showing first 50 affected entries in server-rendered view.

References (9)