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CVE-2026-64537
bridge: cfm: reject invalid CCM interval at configuration time
Overview
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).

Details
INFO

Published Date :

July 27, 2026, 9:17 p.m.

Last Modified :

July 27, 2026, 9:17 p.m.

Remotely Exploit :

No

Source :

416baaa9-dc9f-4396-8d5f-8c081fb06d67
Impact
Affected Products

The following products are affected by CVE-2026-64537 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Linux linux_kernel
: Total Affected Vendor : 1 | Products : 1
Solution
Validate CCM interval configuration to prevent immediate worker firing and resource exhaustion.
  • Constrain exp_interval to the valid range in netlink policy.
  • Reject CCM TX if exp_interval has not been configured.
  • Update the Linux kernel to the resolved version.
References
References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2026-64537.

URL Resource
https://git.kernel.org/stable/c/2870056a78961e0fecd652362ee9d3fcfd24a8a6
https://git.kernel.org/stable/c/53788b134519e995699ea3721969c96a08d64575
https://git.kernel.org/stable/c/865643640b5b5c4579b32d7a55ac9ad648362eaa
https://git.kernel.org/stable/c/a090880c1f544589427e5b7050c40fb211ccecb4
https://git.kernel.org/stable/c/b42aeb58317f12024734759ff745856b53948873
https://git.kernel.org/stable/c/f0f5eb59a97ece0d85de8cfa95dc18c609302a8b
https://git.kernel.org/stable/c/f3e02edd8322b31b8e6517faa6ba053bf29d1e26
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-64537 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-64537 weaknesses.

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2026-64537 vulnerability anywhere in the article.

Results are limited to the first 20 news articles due to potential performance issues.

The following table lists the changes that have been made to the CVE-2026-64537 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67

    Jul. 27, 2026

    Action Type Old Value New Value
    Added Affected [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '2be665c3940d367e0a2a8128eb4985ce323f99a3', 'lessThan': '2870056a78961e0fecd652362ee9d3fcfd24a8a6', 'versionType': 'git'}, {'status': 'affected', 'version': '2be665c3940d367e0a2a8128eb4985ce323f99a3', 'lessThan': 'f0f5eb59a97ece0d85de8cfa95dc18c609302a8b', 'versionType': 'git'}, {'status': 'affected', 'version': '2be665c3940d367e0a2a8128eb4985ce323f99a3', 'lessThan': '53788b134519e995699ea3721969c96a08d64575', 'versionType': 'git'}, {'status': 'affected', 'version': '2be665c3940d367e0a2a8128eb4985ce323f99a3', 'lessThan': 'b42aeb58317f12024734759ff745856b53948873', 'versionType': 'git'}, {'status': 'affected', 'version': '2be665c3940d367e0a2a8128eb4985ce323f99a3', 'lessThan': 'a090880c1f544589427e5b7050c40fb211ccecb4', 'versionType': 'git'}, {'status': 'affected', 'version': '2be665c3940d367e0a2a8128eb4985ce323f99a3', 'lessThan': '865643640b5b5c4579b32d7a55ac9ad648362eaa', 'versionType': 'git'}, {'status': 'affected', 'version': '2be665c3940d367e0a2a8128eb4985ce323f99a3', 'lessThan': 'f3e02edd8322b31b8e6517faa6ba053bf29d1e26', 'versionType': 'git'}], 'programFiles': ['net/bridge/br_cfm.c', 'net/bridge/br_cfm_netlink.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '5.11'}, {'status': 'unaffected', 'version': '0', 'lessThan': '5.11', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '5.15.212', 'versionType': 'semver', 'lessThanOrEqual': '5.15.*'}, {'status': 'unaffected', 'version': '6.1.178', 'versionType': 'semver', 'lessThanOrEqual': '6.1.*'}, {'status': 'unaffected', 'version': '6.6.145', 'versionType': 'semver', 'lessThanOrEqual': '6.6.*'}, {'status': 'unaffected', 'version': '6.12.97', 'versionType': 'semver', 'lessThanOrEqual': '6.12.*'}, {'status': 'unaffected', 'version': '6.18.40', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.1.5', 'versionType': 'semver', 'lessThanOrEqual': '7.1.*'}, {'status': 'unaffected', 'version': '7.2-rc1', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['net/bridge/br_cfm.c', 'net/bridge/br_cfm_netlink.c'], 'defaultStatus': 'affected'}]
    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).
    Added Reference https://git.kernel.org/stable/c/2870056a78961e0fecd652362ee9d3fcfd24a8a6
    Added Reference https://git.kernel.org/stable/c/53788b134519e995699ea3721969c96a08d64575
    Added Reference https://git.kernel.org/stable/c/865643640b5b5c4579b32d7a55ac9ad648362eaa
    Added Reference https://git.kernel.org/stable/c/a090880c1f544589427e5b7050c40fb211ccecb4
    Added Reference https://git.kernel.org/stable/c/b42aeb58317f12024734759ff745856b53948873
    Added Reference https://git.kernel.org/stable/c/f0f5eb59a97ece0d85de8cfa95dc18c609302a8b
    Added Reference https://git.kernel.org/stable/c/f3e02edd8322b31b8e6517faa6ba053bf29d1e26
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
CVSS
Vulnerability Scoring Details
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