CVE-2026-64537

Local denial of service via zero-delay CCM loop

Published Jul 27, 2026 · Updated Jul 27, 2026

Denial of service in the Linux Kernel allows local users to exhaust kernel memory through an invalid bridge CFM CCM interval. ccm_tx_work_expired() converts an unset or out-of-range exp_interval to a zero delay, immediately requeues itself, and allocates skbs until OOM. Reaching the flaw requires local bridge interface configuration privileges, normally effective UID 0 or CAP_NET_ADMIN; the result is host-wide memory exhaustion and service interruption.

CVSS severityUnavailable
Unscored
EPSS probability0.17%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in the Linux Kernel allows local users to exhaust kernel memory through an invalid bridge CFM CCM interval. ccm_tx_work_expired() converts an unset or out-of-range exp_interval to a zero delay, immediately requeues itself, and allocates skbs until OOM. Reaching the flaw requires local bridge interface configuration privileges, normally effective UID 0 or CAP_NET_ADMIN; the result is host-wide memory exhaustion and service interruption.

The record

CVE
CVE-2026-64537
Published
Jul 27, 2026
Updated
Jul 27, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
T1499.001
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Jul 27, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 27, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=2be665c3940d367e0a2a8128eb4985ce323f99a3 <2870056a78961e0fecd652362ee9d3fcfd24a8a6
  2. Affected versionversion=2be665c3940d367e0a2a8128eb4985ce323f99a3 <53788b134519e995699ea3721969c96a08d64575
  3. Affected versionversion=2be665c3940d367e0a2a8128eb4985ce323f99a3 <865643640b5b5c4579b32d7a55ac9ad648362eaa
  4. Affected versionversion=2be665c3940d367e0a2a8128eb4985ce323f99a3 <a090880c1f544589427e5b7050c40fb211ccecb4
  5. Affected versionversion=2be665c3940d367e0a2a8128eb4985ce323f99a3 <b42aeb58317f12024734759ff745856b53948873
  6. Affected versionversion=2be665c3940d367e0a2a8128eb4985ce323f99a3 <f0f5eb59a97ece0d85de8cfa95dc18c609302a8b
  7. Affected versionversion=2be665c3940d367e0a2a8128eb4985ce323f99a3 <f3e02edd8322b31b8e6517faa6ba053bf29d1e26
  8. Affected versionversion=5.11

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

The Linux Kernel Organization · Linux Kernelversion=2be665c3940d367e0a2a8128eb4985ce323f99a3 <2870056a78961e0fecd652362ee9d3fcfd24a8a6; version=2be665c3940d367e0a2a8128eb4985ce323f99a3 <53788b134519e995699ea3721969c96a08d64575; version=2be665c3940d367e0a2a8128eb4985ce323f99a3 <865643640b5b5c4579b32d7a55ac9ad648362eaa; version=2be665c3940d367e0a2a8128eb4985ce323f99a3 <a090880c1f544589427e5b7050c40fb211ccecb4; version=2be665c3940d367e0a2a8128eb4985ce323f99a3 <b42aeb58317f12024734759ff745856b53948873; version=2be665c3940d367e0a2a8128eb4985ce323f99a3 <f0f5eb59a97ece0d85de8cfa95dc18c609302a8b; version=2be665c3940d367e0a2a8128eb4985ce323f99a3 <f3e02edd8322b31b8e6517faa6ba053bf29d1e26; version=5.11

Published CVSS scores

No CVSS assessment is available in this record.

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499.001OS Exhaustion Flood

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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