CVE-2026-64537

Summary

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 Software

VendorProductVersion RangeStatus
LinuxLinux2be665c3940d367e0a2a8128eb4985ce323f99a3 < 2870056a78961e0fecd652362ee9d3fcfd24a8a6affected
LinuxLinux2be665c3940d367e0a2a8128eb4985ce323f99a3 < f0f5eb59a97ece0d85de8cfa95dc18c609302a8baffected
LinuxLinux2be665c3940d367e0a2a8128eb4985ce323f99a3 < 53788b134519e995699ea3721969c96a08d64575affected
LinuxLinux2be665c3940d367e0a2a8128eb4985ce323f99a3 < b42aeb58317f12024734759ff745856b53948873affected
LinuxLinux2be665c3940d367e0a2a8128eb4985ce323f99a3 < a090880c1f544589427e5b7050c40fb211ccecb4affected
LinuxLinux2be665c3940d367e0a2a8128eb4985ce323f99a3 < 865643640b5b5c4579b32d7a55ac9ad648362eaaaffected
LinuxLinux2be665c3940d367e0a2a8128eb4985ce323f99a3 < f3e02edd8322b31b8e6517faa6ba053bf29d1e26affected
LinuxLinux5.11affected
LinuxLinux0 < 5.11unaffected
LinuxLinux5.15.212 <= 5.15.*unaffected
LinuxLinux6.1.178 <= 6.1.*unaffected
LinuxLinux6.6.145 <= 6.6.*unaffected
LinuxLinux6.12.97 <= 6.12.*unaffected
LinuxLinux6.18.40 <= 6.18.*unaffected
LinuxLinux7.1.5 <= 7.1.*unaffected
LinuxLinux7.2-rc1 <= *unaffected

Weaknesses

References