---
cve: "CVE-2026-64537"
severity: "LOW"
cvss: 3.1
epss: "17%"
vendor: "Linux"
kev: false
exploited: false
published: "2026-07-27 21:17:05"
tags: [cve, security, low]
source: tsecurity.de CVE-Dossier
exported: "2026-09-15T18:50:50+02:00"
---

# CVE-2026-64537

> 3.1 LOW

## Beschreibung

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).

## Patch verfügbar (OSV)

- Kernel ≥ 5.15.212
- Kernel ≥ 6.1.178
- Kernel ≥ 6.6.145
- Kernel ≥ 6.12.97
- Kernel ≥ 6.18.40
- Kernel ≥ 7.1.5

## Referenzen

- <https://git.kernel.org/stable/c/2870056a78961e0fecd652362ee9d3fcfd24a8a6>
- <https://git.kernel.org/stable/c/f0f5eb59a97ece0d85de8cfa95dc18c609302a8b>
- <https://git.kernel.org/stable/c/53788b134519e995699ea3721969c96a08d64575>
- <https://git.kernel.org/stable/c/b42aeb58317f12024734759ff745856b53948873>
- <https://git.kernel.org/stable/c/a090880c1f544589427e5b7050c40fb211ccecb4>
- <https://git.kernel.org/stable/c/865643640b5b5c4579b32d7a55ac9ad648362eaa>
- <https://git.kernel.org/stable/c/f3e02edd8322b31b8e6517faa6ba053bf29d1e26>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-64537) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_