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CVE-2026-64537 (GCVE-0-2026-64537)

Vulnerability from cvelistv5 – Published: 2026-07-27 20:10 – Updated: 2026-08-17 04:57
VLAI
Title
bridge: cfm: reject invalid CCM interval at configuration time
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).
Severity
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 2be665c3940d367e0a2a8128eb4985ce323f99a3 , < 2870056a78961e0fecd652362ee9d3fcfd24a8a6 (git)
Affected: 2be665c3940d367e0a2a8128eb4985ce323f99a3 , < f0f5eb59a97ece0d85de8cfa95dc18c609302a8b (git)
Affected: 2be665c3940d367e0a2a8128eb4985ce323f99a3 , < 53788b134519e995699ea3721969c96a08d64575 (git)
Affected: 2be665c3940d367e0a2a8128eb4985ce323f99a3 , < b42aeb58317f12024734759ff745856b53948873 (git)
Affected: 2be665c3940d367e0a2a8128eb4985ce323f99a3 , < a090880c1f544589427e5b7050c40fb211ccecb4 (git)
Affected: 2be665c3940d367e0a2a8128eb4985ce323f99a3 , < 865643640b5b5c4579b32d7a55ac9ad648362eaa (git)
Affected: 2be665c3940d367e0a2a8128eb4985ce323f99a3 , < f3e02edd8322b31b8e6517faa6ba053bf29d1e26 (git)
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Linux Linux Affected: 5.11
Unaffected: 0 , < 5.11 (semver)
Unaffected: 5.15.212 , ≤ 5.15.* (semver)
Unaffected: 6.1.178 , ≤ 6.1.* (semver)
Unaffected: 6.6.145 , ≤ 6.6.* (semver)
Unaffected: 6.12.97 , ≤ 6.12.* (semver)
Unaffected: 6.18.40 , ≤ 6.18.* (semver)
Unaffected: 7.1.5 , ≤ 7.1.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
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          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbridge: cfm: reject invalid CCM interval at configuration time\n\nccm_tx_work_expired() re-arms itself via queue_delayed_work() using\nthe configured exp_interval converted by interval_to_us(). When\nexp_interval is BR_CFM_CCM_INTERVAL_NONE or out of range,\ninterval_to_us() returns 0, causing the worker to fire immediately in\na tight loop that allocates skbs until OOM.\n\nFix this by validating exp_interval at configuration time:\n\n - Constrain IFLA_BRIDGE_CFM_CC_CONFIG_EXP_INTERVAL to the valid range\n   [BR_CFM_CCM_INTERVAL_3_3_MS, BR_CFM_CCM_INTERVAL_10_MIN] in the\n   netlink policy so userspace cannot set an invalid value.\n\n - Reject starting CCM TX in br_cfm_cc_ccm_tx() when exp_interval has\n   not yet been configured (defaults to 0 from kzalloc)."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-17T04:57:13.368Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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    "cveId": "CVE-2026-64537",
    "datePublished": "2026-07-27T20:10:32.210Z",
    "dateReserved": "2026-07-19T15:36:31.795Z",
    "dateUpdated": "2026-08-17T04:57:13.368Z",
    "state": "PUBLISHED"
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      "date": "2026-09-15",
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    },
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    "redhat_vex": {
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      "current_release_date": "2026-08-05T12:42:09+00:00",
      "cve": "CVE-2026-64537",
      "id": "CVE-2026-64537",
      "initial_release_date": "2026-07-27T00:00:00+00:00",
      "product_status:known_not_affected": "274",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: bridge: cfm: reject invalid CCM interval at configuration time",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-64537.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-09-15T01:46:31Z",
      "cve": "CVE-2026-64537",
      "id": "CVE-2026-64537",
      "initial_release_date": "2026-07-28T17:08:10Z",
      "product_status:first_fixed": "65",
      "product_status:known_affected": "602",
      "product_status:known_not_affected": "147",
      "product_status:recommended": "46",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-64537",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-64537.json",
      "version": "9"
    }
  }
}



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