CVE-2026-72121
- Source
- https://cve.org/CVERecord?id=CVE-2026-72121
- Import Source
- https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-72121.json
- JSON Data
- https://api.osv.dev/v1/vulns/CVE-2026-72121
- Downstream
- Published
- 2026-08-15T05:52:59Z
- Modified
- 2026-10-08T02:51:45Z
- Severity
-
- 8.8 (High) CVSS_V3 - CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H CVSS Calculator
- Summary
- can: bcm: add locking when updating filter and timer values
- Details
-
In the Linux kernel, the following vulnerability has been resolved:
can: bcm: add locking when updating filter and timer values
KCSAN detected a simultaneous access to timer values that can be overwritten in bcm_rx_setup() when updating timer and filter content while bcm_rx_handler(), bcm_rx_timeout_handler() or bcm_rx_thr_handler() run concurrently on incoming CAN traffic.
Protect the timer (ival1/ival2/kt_ival1/kt_ival2/kt_lastmsg) and filter (nframes/flags/frames/last_frames) updates in bcm_rx_setup() with a new per-op bcm_rx_update_lock, taken with the matching scope in the RX handlers. memcpy_from_msg() is staged into a temporary buffer before the lock is taken, since it can sleep and must not run under a spinlock.
hrtimer_cancel() is always called without bcm_rx_update_lock held, since bcm_rx_timeout_handler()/bcm_rx_thr_handler() take the same lock and a running callback would otherwise deadlock against the canceller.
Also close a related race: bcm_rx_setup() cleared the RTR flag in the stored reply frame's can_id as a separate, unprotected step after the frame content was already installed, so a concurrent bcm_rx_handler() could transmit a stale reply with CAN_RTR_FLAG still set. Fold that normalization into the initial frame preparation instead (on the staged buffer for updates, directly on op->frames pre-registration for new ops), so the installed frame is always atomically self-consistent.
bcm_rx_handler()'s RX_RTR_FRAME check now takes a lock-protected snapshot of op->flags before deciding whether to call bcm_can_tx(), but does not hold the lock across that call.
Also take a lock-protected snapshot of the currframe in bcm_can_tx() to avoid partly overwrites by content updates in bcm_tx_setup(). Finally check if a TX_RESET_MULTI_IDX/SETTIMER might have reset op->currframe between the two locked sections in bcm_can_tx().
Omit calling hrtimer_forward() with zero interval in bcm_rx_thr_handler(). kt_ival2 may have been concurrently cleared by bcm_rx_setup() before it cancels this timer, so check kt_ival2 inside the bcm_rx_update_lock.
- Database specific
{ "cna_assigner": "Linux", "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/72xxx/CVE-2026-72121.json" }- References
-
- https://git.kernel.org/stable/c/19b1994069dd29478ba767de1f98f14a088198dc
- https://git.kernel.org/stable/c/749179c2e25b95d22499ed29096b3e02d6dfd2b4
- https://git.kernel.org/stable/c/834cbca3b12e46887f7a9b35f1981a888360ea4c
- https://git.kernel.org/stable/c/96994180bd7b248b0cc698afe926e23fc1bda59b
- https://git.kernel.org/stable/c/a7c369e7da8203e2b5be12bbcac7b9ab2ed5b658
- https://git.kernel.org/stable/c/a7eb6db1cd3f7b556a301dc1265945ad112089f7
- https://git.kernel.org/stable/c/caa8704a7f3cb7806331596195385437126ecb3a
- https://git.kernel.org/stable/c/fc9f5ee1b073bd233d9c604e338af4ebb42cbc33
- https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/72xxx/CVE-2026-72121.json
- https://nvd.nist.gov/vuln/detail/CVE-2026-72121
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Affected packages
Git / git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Affected ranges
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced7595de7bc56e0e52b74e56c90f7e247bf626d628Fixed96994180bd7b248b0cc698afe926e23fc1bda59b
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introducedfbd8fdc2b218e979cfe422b139b8f74c12419d1fFixedcaa8704a7f3cb7806331596195385437126ecb3a
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced2a437b86ac5a9893c902f30ef66815bf13587bf6Fixeda7c369e7da8203e2b5be12bbcac7b9ab2ed5b658
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced76c84c3728178b2d38d5604e399dfe8b0752645eFixeda7eb6db1cd3f7b556a301dc1265945ad112089f7
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introducedcc55dd28c20a6611e30596019b3b2f636819a4c0Fixed834cbca3b12e46887f7a9b35f1981a888360ea4c
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introducedc2aba69d0c36a496ab4f2e81e9c2b271f2693fd7Fixed19b1994069dd29478ba767de1f98f14a088198dcFixedfc9f5ee1b073bd233d9c604e338af4ebb42cbc33Fixed749179c2e25b95d22499ed29096b3e02d6dfd2b4
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced5.10.238Fixed5.10.265
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced5.15.185Fixed5.15.216
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced6.1.141Fixed6.1.183
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced6.6.93Fixed6.6.148
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced6.12.31Fixed6.12.101
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced5.4.294Fixed5.5
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced6.14.9Fixed6.15
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced8f1c022541bf5a923c8d6fa483112c15250f30a4
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introducedc4e8a172501e677ebd8ea9d9161d97dc4df56fbd
Affected versions
v5.*
v6.*
Linux / Kernel
Package
- Name
- Kernel
Affected ranges
- Type
- ECOSYSTEM
- Events
-
Introduced0 Unknown introduced version / All previous versions are affectedFixed5.10.265
- Type
- ECOSYSTEM
- Events
-
Introduced5.11.0Fixed5.15.216
- Type
- ECOSYSTEM
- Events
-
Introduced5.16.0Fixed6.1.183
- Type
- ECOSYSTEM
- Events
-
Introduced6.2.0Fixed6.6.148
- Type
- ECOSYSTEM
- Events
-
Introduced6.7.0Fixed6.12.101
- Type
- ECOSYSTEM
- Events
-
Introduced6.13.0Fixed6.18.42
- Type
- ECOSYSTEM
- Events
-
Introduced6.15.0Fixed7.1.5