CVE-2026-64537
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).
Affected versions
Linux kernel versions
5.11
and later are affected. Fixed in
5.15.212,
6.1.178,
6.6.145,
6.12.97,
6.18.40,
7.1.5,
7.2-rc1
and their respective stable series.
References
7 totalFrequently asked questions
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What is CVE-2026-64537?
CVE-2026-64537 is a unscored severity Linux kernel vulnerability . It affects Linux kernel versions from 5.11 onward and has been patched in 5.15.212, 6.1.178, 6.6.145 and others. CVE-2026-64537 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
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Is there a patch available for CVE-2026-64537?
Yes. CVE-2026-64537 has been patched. Fixed versions include 5.15.212, 6.1.178, 6.6.145 and others. If you are running Linux kernel 5.11 or later up to the fix versions, apply the relevant patch for your kernel branch.
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Is CVE-2026-64537 actively exploited?
No. CVE-2026-64537 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.