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NVD / CVE Program· CNA Linux

CVE-2026-23393: bridge: cfm: Fix race condition in peer_mep deletion

Noroxi assessment

Priority: Monitor (action score 31/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.10% (FIRST EPSS).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Linux Linux 1fd81151f65927fd9edb8ecd12ad45527dbbe5ab, 3715a00855316066cdda69d43648336367422127, d8f35767bacb3c7769d470a41cf161e3f3c07e70.

Low priority for now. Upgrade to Linux Linux 1fd81151f65927fd9edb8ecd12ad45527dbbe5ab, 3715a00855316066cdda69d43648336367422127, d8f35767bacb3c7769d470a41cf161e3f3c07e70 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

HighCVSS 7.8 · v3.1—No exploit Fix available
Published
Mar 25, 2026
Updated
Aug 5, 2026
EPSS
0.1% · 0th percentile

Report tools

JSON

Action score

31

Monitor

Low priority for now.

CVSS
31 / 40 · 7.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

CNA vs NVD score

NVD
—
CNA · Linux
7.8
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

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Noroxi analysis

What does it mean in your environment?

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
linuxlinux kernel

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • linux linux kernel5.11.1 and later · before 6.12.78
  • linux linux kernel6.13 and later · before 6.18.20
  • linux linux kernel6.19 and later · before 6.19.10
  • linux linux kernel5.11
  • linux linux kernel7.0

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 5.11affected
    • dc32cbb3dbd7da38c700d6e0fc6354df24920525 and later · before e89dbd2736a45f0507949af4748cbbf3ff793146affected · git
    • dc32cbb3dbd7da38c700d6e0fc6354df24920525 and later · before d8f35767bacb3c7769d470a41cf161e3f3c07e70affected · git
    • dc32cbb3dbd7da38c700d6e0fc6354df24920525 and later · before 1fd81151f65927fd9edb8ecd12ad45527dbbe5abaffected · git
    • dc32cbb3dbd7da38c700d6e0fc6354df24920525 and later · before 3715a00855316066cdda69d43648336367422127affected · git
    • before 5.11not affected · semver
    • 6.12.78 and later · up to and including 6.12.*not affected · semver
    • 6.18.20 and later · up to and including 6.18.*not affected · semver
    • 6.19.10 and later · up to and including 6.19.*not affected · semver
    • 7.0 and laternot affected · original_commit_for_fix

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12linuxfrom 0—
Debian:13linuxbefore 6.12.85-16.12.85-1
Debian:14linuxbefore 6.19.10-16.19.10-1
SUSE:Linux Enterprise Live Patching 15 SP4kernel-livepatch-SLE15-SP4_Update_41before 21-150400.2.121-150400.2.1
SUSE:Linux Enterprise Live Patching 15 SP4kernel-livepatch-SLE15-SP4_Update_43before 17-150400.2.117-150400.2.1
SUSE:Linux Enterprise Live Patching 15 SP4kernel-livepatch-SLE15-SP4_Update_44before 16-150400.2.116-150400.2.1
SUSE:Linux Enterprise Live Patching 15 SP4kernel-livepatch-SLE15-SP4_Update_45before 14-150400.2.114-150400.2.1
SUSE:Linux Enterprise Live Patching 15 SP4kernel-livepatch-SLE15-SP4_Update_46before 10-150400.2.110-150400.2.1
SUSE:Linux Enterprise Live Patching 15 SP4kernel-livepatch-SLE15-SP4_Update_49before 6-150400.2.16-150400.2.1
SUSE:Linux Enterprise Live Patching 15 SP4kernel-livepatch-SLE15-SP4_Update_51before 5-150400.2.15-150400.2.1
SUSE:Linux Enterprise Live Patching 15 SP4kernel-livepatch-SLE15-SP4_Update_52before 4-150400.2.14-150400.2.1
SUSE:Linux Enterprise Live Patching 15 SP5kernel-livepatch-SLE15-SP5_Update_27before 21-150500.2.221-150500.2.2
SUSE:Linux Enterprise Live Patching 15 SP5kernel-livepatch-SLE15-SP5_Update_28before 20-150500.2.220-150500.2.2
SUSE:Linux Enterprise Live Patching 15 SP5kernel-livepatch-SLE15-SP5_Update_30before 15-150500.2.215-150500.2.2
SUSE:Linux Enterprise Live Patching 15 SP5kernel-livepatch-SLE15-SP5_Update_31before 13-150500.2.213-150500.2.2
SUSE:Linux Enterprise Live Patching 15 SP5kernel-livepatch-SLE15-SP5_Update_37before 6-150500.2.26-150500.2.2
SUSE:Linux Enterprise Live Patching 15 SP5kernel-livepatch-SLE15-SP5_Update_39before 4-150500.2.24-150500.2.2
SUSE:Linux Enterprise Live Patching 15 SP6kernel-defaultbefore 6.4.0-150600.23.112.16.4.0-150600.23.112.1
SUSE:Linux Enterprise Live Patching 15 SP6kernel-livepatch-SLE15-SP6_Update_12before 20-150600.2.220-150600.2.2
SUSE:Linux Enterprise Live Patching 15 SP6kernel-livepatch-SLE15-SP6_Update_13before 18-150600.2.218-150600.2.2
SUSE:Linux Enterprise Live Patching 15 SP6kernel-livepatch-SLE15-SP6_Update_22before 6-150600.2.26-150600.2.2
SUSE:Linux Enterprise Live Patching 15 SP6kernel-livepatch-SLE15-SP6_Update_23before 5-150600.2.25-150600.2.2
SUSE:Linux Enterprise Live Patching 15 SP6kernel-livepatch-SLE15-SP6_Update_25before 3-150600.2.23-150600.2.2
SUSE:Linux Enterprise Live Patching 15 SP6kernel-livepatch-SLE15-SP6_Update_26before 1-150600.13.3.11-150600.13.3.1

+58

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-31431crypto: algif_aead - Revert to operating out-of-placeKEV
    90Now
  • CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe…KEV
    89Now
  • CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
    85Now

Published before and after this one in the same product

  • ← EarlierCVE-2026-23387Mar 25, 2026 · pinctrl: cirrus: cs42l43: Fix double-put in cs42l43_pin_probe()
    31Monitor
  • ← EarlierCVE-2026-23390Mar 25, 2026 · tracing/dma: Cap dma_map_sg tracepoint arrays to prevent buffer overflow
    31Monitor
  • Later →CVE-2026-23394Mar 25, 2026 · af_unix: Give up GC if MSG_PEEK intervened.
    18Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux1fd81151f65927fd9edb8ecd12ad45527dbbe5abVendor (CNA)
Linux Linux3715a00855316066cdda69d43648336367422127Vendor (CNA)
Linux Linuxd8f35767bacb3c7769d470a41cf161e3f3c07e70Vendor (CNA)
Linux Linuxe89dbd2736a45f0507949af4748cbbf3ff793146Vendor (CNA)
debian:linux6.12.85-1 · Debian:13Package registry (OSV)
suse:kernel-64kb6.4.0-150600.23.112.1 · SUSE:Linux Enterprise Server 15 SP6-LTSSPackage registry (OSV)
suse:kernel-default6.4.0-150600.23.112.1 · SUSE:Linux Enterprise Live Patching 15 SP6Package registry (OSV)
suse:kernel-default-base6.4.0-150600.23.112.1.150600.12.52.1 · SUSE:Linux Enterprise Server 15 SP6-LTSSPackage registry (OSV)
suse:kernel-docs6.4.0-150600.23.112.1 · SUSE:Linux Enterprise Server 15 SP6-LTSSPackage registry (OSV)
suse:kernel-livepatch-MICRO-6-0_Update_1014-1.1 · SUSE:Linux Micro 6.1Package registry (OSV)
suse:kernel-livepatch-MICRO-6-0_Update_1113-1.1 · SUSE:Linux Micro 6.1Package registry (OSV)
suse:kernel-livepatch-MICRO-6-0_Update_1213-1.1 · SUSE:Linux Micro 6.1Package registry (OSV)
suse:kernel-livepatch-SLE15-SP6_Update_261-150600.13.3.1 · SUSE:Linux Enterprise Live Patching 15 SP6Package registry (OSV)
suse:kernel-obs-build6.4.0-150600.23.112.1 · SUSE:Linux Enterprise Server 15 SP6-LTSSPackage registry (OSV)
suse:kernel-source6.4.0-150600.23.112.1 · SUSE:Linux Enterprise Server 15 SP6-LTSSPackage registry (OSV)
suse:kernel-syms6.4.0-150600.23.112.1 · SUSE:Linux Enterprise Server 15 SP6-LTSSPackage registry (OSV)
suse:kernel-zfcpdump6.4.0-150600.23.112.1 · SUSE:Linux Enterprise Server 15 SP6-LTSSPackage registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

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

CVSS vector

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

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (3 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records