# CVE-2026-72117: can: bcm: fix data race on rx_stamp/rx_ifindex in bcm_rx_handler()

Status: published. Published: 2026-08-15. Updated: 2026-11-06.

In the Linux kernel, the following vulnerability has been resolved:

can: bcm: fix data race on rx_stamp/rx_ifindex in bcm_rx_handler()

For an rx op subscribed on all interfaces (ifindex == 0), the same op
is registered once in the shared per-netns wildcard filter list, so
bcm_rx_handler() can run concurrently on different CPUs for frames
arriving on different net devices.

op->rx_stamp and op->rx_ifindex were written before bcm_rx_update_lock was
taken, allowing concurrent writers to race each other - including a torn
store of the 64-bit rx_stamp on 32-bit platforms.

Beyond a torn store bcm_send_to_user() must report the timestamp/ifindex
of the very same frame whose content it is delivering. So the assignment
is placed in the same unbroken bcm_rx_update_lock section as the content
comparison.

As a side effect, the RTR-request frame feature (which never reach
bcm_send_to_user()) no longer updates rx_stamp/rx_ifindex, since only
the notification path needs them.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- Linux / Linux: ≥ ffd980f976e7fd666c2e61bf8ab35107efd11828; < b64f60c468d149aca22ea56bb842b9730215aaa5 (affected, git); ≥ ffd980f976e7fd666c2e61bf8ab35107efd11828; < c8a5d7cb095d3b12bd9dcf752d6ca0ff50872ac5 (affected, git); ≥ ffd980f976e7fd666c2e61bf8ab35107efd11828; < 4b97410f4bba18d2ee2784c8e089104f387bc27c (affected, git); ≥ ffd980f976e7fd666c2e61bf8ab35107efd11828; < 5f246b96ab47523ec9b8ea870b5c567a3cb1eb1c (affected, git); ≥ ffd980f976e7fd666c2e61bf8ab35107efd11828; < 656ff69ef235699035e57d9e1ae417e62a38aa7f (affected, git); ≥ ffd980f976e7fd666c2e61bf8ab35107efd11828; < 136de17f38630307991c59aa7080012a99451783 (affected, git); ≥ ffd980f976e7fd666c2e61bf8ab35107efd11828; < c312b750bb5ac3348cfc85dab25e90937bd4d251 (affected, git); ≥ ffd980f976e7fd666c2e61bf8ab35107efd11828; < 58fd6cbc8541216af1d7ed272ea7ac2b66d50fd8 (affected, git). Source: CNA: Linux
- Linux / Linux: 2.6.25 (affected); ≥ 0; < 2.6.25 (unaffected, semver); ≥ 5.10.265; ≤ 5.10.* (unaffected, semver); ≥ 5.15.216; ≤ 5.15.* (unaffected, semver); ≥ 6.1.183; ≤ 6.1.* (unaffected, semver); ≥ 6.6.148; ≤ 6.6.* (unaffected, semver); ≥ 6.12.101; ≤ 6.12.* (unaffected, semver); ≥ 6.18.42; ≤ 6.18.* (unaffected, semver); ≥ 7.1.5; ≤ 7.1.* (unaffected, semver); ≥ 7.2; ≤ * (unaffected, original_commit_for_fix). Source: CNA: Linux

## Severity and prioritization

- CISA KEV: No listing in collected sources

- EPSS: 0.22% as of 2026-11-06; percentile 12.13%

- SSVC: exploitation none; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: Not reported

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://git.kernel.org/stable/c/b64f60c468d149aca22ea56bb842b9730215aaa5 (CNA: Linux)

- https://git.kernel.org/stable/c/c8a5d7cb095d3b12bd9dcf752d6ca0ff50872ac5 (CNA: Linux)

- https://git.kernel.org/stable/c/4b97410f4bba18d2ee2784c8e089104f387bc27c (CNA: Linux)

- https://git.kernel.org/stable/c/5f246b96ab47523ec9b8ea870b5c567a3cb1eb1c (CNA: Linux)

- https://git.kernel.org/stable/c/656ff69ef235699035e57d9e1ae417e62a38aa7f (CNA: Linux)

- https://git.kernel.org/stable/c/136de17f38630307991c59aa7080012a99451783 (CNA: Linux)

- https://git.kernel.org/stable/c/c312b750bb5ac3348cfc85dab25e90937bd4d251 (CNA: Linux)

- https://git.kernel.org/stable/c/58fd6cbc8541216af1d7ed272ea7ac2b66d50fd8 (CNA: Linux)

- https://git.kernel.org/stable/c/136de17f38630307991c59aa7080012a99451783 (416baaa9-dc9f-4396-8d5f-8c081fb06d67)

- https://git.kernel.org/stable/c/4b97410f4bba18d2ee2784c8e089104f387bc27c (416baaa9-dc9f-4396-8d5f-8c081fb06d67)

- https://git.kernel.org/stable/c/58fd6cbc8541216af1d7ed272ea7ac2b66d50fd8 (416baaa9-dc9f-4396-8d5f-8c081fb06d67)

- https://git.kernel.org/stable/c/5f246b96ab47523ec9b8ea870b5c567a3cb1eb1c (416baaa9-dc9f-4396-8d5f-8c081fb06d67)

- https://git.kernel.org/stable/c/656ff69ef235699035e57d9e1ae417e62a38aa7f (416baaa9-dc9f-4396-8d5f-8c081fb06d67)

- https://git.kernel.org/stable/c/b64f60c468d149aca22ea56bb842b9730215aaa5 (416baaa9-dc9f-4396-8d5f-8c081fb06d67)

- https://git.kernel.org/stable/c/c312b750bb5ac3348cfc85dab25e90937bd4d251 (416baaa9-dc9f-4396-8d5f-8c081fb06d67)

- https://git.kernel.org/stable/c/c8a5d7cb095d3b12bd9dcf752d6ca0ff50872ac5 (416baaa9-dc9f-4396-8d5f-8c081fb06d67)

## Provenance

- CNA: Linux: https://www.cve.org/CVERecord?id=CVE-2026-72117; retrieved 2026-11-06; source updated 2026-11-06

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-72117; retrieved 2026-11-06; source updated 2026-11-06

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-72117; retrieved 2026-11-06; source updated Not reported

Revision: e897527a05c281dcaf8e99826af03f4ee6472a74fb3625ed382d7dec4deb2f78

Canonical: https://y2.dev/cve/CVE-2026-72117

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