In the Linux kernel, the following vulnerability has been resolved:

bridge: cfm: reject invalid CCM interval at configuration time

ccm_tx_work_expired() re-arms itself via queue_delayed_work() using
the configured exp_interval converted by interval_to_us(). When
exp_interval is BR_CFM_CCM_INTERVAL_NONE or out of range,
interval_to_us() returns 0, causing the worker to fire immediately in
a tight loop that allocates skbs until OOM.

Fix this by validating exp_interval at configuration time:

- Constrain IFLA_BRIDGE_CFM_CC_CONFIG_EXP_INTERVAL to the valid range
[BR_CFM_CCM_INTERVAL_3_3_MS, BR_CFM_CCM_INTERVAL_10_MIN] in the
netlink policy so userspace cannot set an invalid value.

- Reject starting CCM TX in br_cfm_cc_ccm_tx() when exp_interval has
not yet been configured (defaults to 0 from kzalloc).

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Advisories
Source ID Title
Debian DSA Debian DSA DSA-6405-1 linux security update
Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Tue, 04 Aug 2026 14:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-20
CWE-703

Wed, 29 Jul 2026 12:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-835
References
Metrics threat_severity

None

cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

threat_severity

Low


Tue, 28 Jul 2026 16:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-20
CWE-703

Mon, 27 Jul 2026 20:30:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: bridge: cfm: reject invalid CCM interval at configuration time ccm_tx_work_expired() re-arms itself via queue_delayed_work() using the configured exp_interval converted by interval_to_us(). When exp_interval is BR_CFM_CCM_INTERVAL_NONE or out of range, interval_to_us() returns 0, causing the worker to fire immediately in a tight loop that allocates skbs until OOM. Fix this by validating exp_interval at configuration time: - Constrain IFLA_BRIDGE_CFM_CC_CONFIG_EXP_INTERVAL to the valid range [BR_CFM_CCM_INTERVAL_3_3_MS, BR_CFM_CCM_INTERVAL_10_MIN] in the netlink policy so userspace cannot set an invalid value. - Reject starting CCM TX in br_cfm_cc_ccm_tx() when exp_interval has not yet been configured (defaults to 0 from kzalloc).
Title bridge: cfm: reject invalid CCM interval at configuration time
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-07-27T20:10:32.210Z

Reserved: 2026-07-19T15:36:31.795Z

Link: CVE-2026-64537

cve-icon Vulnrichment

No data.

cve-icon NVD

No data.

cve-icon Redhat

Severity : Low

Publid Date: 2026-07-27T00:00:00Z

Links: CVE-2026-64537 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-08-04T14:00:03Z

Weaknesses