FKIE_CVE-2026-72121

Vulnerability from fkie_nvd - Published: 2026-08-15 06:21 - Updated: 2026-08-19 17:20
Severity
8.8 (High) - CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Summary
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.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/19b1994069dd29478ba767de1f98f14a088198dc
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/749179c2e25b95d22499ed29096b3e02d6dfd2b4
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/834cbca3b12e46887f7a9b35f1981a888360ea4c
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/96994180bd7b248b0cc698afe926e23fc1bda59b
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/a7c369e7da8203e2b5be12bbcac7b9ab2ed5b658
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/a7eb6db1cd3f7b556a301dc1265945ad112089f7
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/caa8704a7f3cb7806331596195385437126ecb3a
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/fc9f5ee1b073bd233d9c604e338af4ebb42cbc33
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/can/bcm.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "96994180bd7b248b0cc698afe926e23fc1bda59b",
              "status": "affected",
              "version": "7595de7bc56e0e52b74e56c90f7e247bf626d628",
              "versionType": "git"
            },
            {
              "lessThan": "caa8704a7f3cb7806331596195385437126ecb3a",
              "status": "affected",
              "version": "fbd8fdc2b218e979cfe422b139b8f74c12419d1f",
              "versionType": "git"
            },
            {
              "lessThan": "a7c369e7da8203e2b5be12bbcac7b9ab2ed5b658",
              "status": "affected",
              "version": "2a437b86ac5a9893c902f30ef66815bf13587bf6",
              "versionType": "git"
            },
            {
              "lessThan": "a7eb6db1cd3f7b556a301dc1265945ad112089f7",
              "status": "affected",
              "version": "76c84c3728178b2d38d5604e399dfe8b0752645e",
              "versionType": "git"
            },
            {
              "lessThan": "834cbca3b12e46887f7a9b35f1981a888360ea4c",
              "status": "affected",
              "version": "cc55dd28c20a6611e30596019b3b2f636819a4c0",
              "versionType": "git"
            },
            {
              "lessThan": "19b1994069dd29478ba767de1f98f14a088198dc",
              "status": "affected",
              "version": "c2aba69d0c36a496ab4f2e81e9c2b271f2693fd7",
              "versionType": "git"
            },
            {
              "lessThan": "fc9f5ee1b073bd233d9c604e338af4ebb42cbc33",
              "status": "affected",
              "version": "c2aba69d0c36a496ab4f2e81e9c2b271f2693fd7",
              "versionType": "git"
            },
            {
              "lessThan": "749179c2e25b95d22499ed29096b3e02d6dfd2b4",
              "status": "affected",
              "version": "c2aba69d0c36a496ab4f2e81e9c2b271f2693fd7",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "8f1c022541bf5a923c8d6fa483112c15250f30a4",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "c4e8a172501e677ebd8ea9d9161d97dc4df56fbd",
              "versionType": "git"
            },
            {
              "lessThan": "5.10.265",
              "status": "affected",
              "version": "5.10.238",
              "versionType": "semver"
            },
            {
              "lessThan": "5.15.216",
              "status": "affected",
              "version": "5.15.185",
              "versionType": "semver"
            },
            {
              "lessThan": "6.1.183",
              "status": "affected",
              "version": "6.1.141",
              "versionType": "semver"
            },
            {
              "lessThan": "6.6.148",
              "status": "affected",
              "version": "6.6.93",
              "versionType": "semver"
            },
            {
              "lessThan": "6.12.101",
              "status": "affected",
              "version": "6.12.31",
              "versionType": "semver"
            },
            {
              "lessThan": "5.5",
              "status": "affected",
              "version": "5.4.294",
              "versionType": "semver"
            },
            {
              "lessThan": "6.15",
              "status": "affected",
              "version": "6.14.9",
              "versionType": "semver"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/can/bcm.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.15"
            },
            {
              "lessThan": "6.15",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.265",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.216",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.183",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.148",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.101",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.42",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.5",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ncan: bcm: add locking when updating filter and timer values\n\nKCSAN detected a simultaneous access to timer values that can be\noverwritten in bcm_rx_setup() when updating timer and filter content\nwhile bcm_rx_handler(), bcm_rx_timeout_handler() or bcm_rx_thr_handler()\nrun concurrently on incoming CAN traffic.\n\nProtect the timer (ival1/ival2/kt_ival1/kt_ival2/kt_lastmsg) and filter\n(nframes/flags/frames/last_frames) updates in bcm_rx_setup() with a new\nper-op bcm_rx_update_lock, taken with the matching scope in the RX\nhandlers. memcpy_from_msg() is staged into a temporary buffer before the\nlock is taken, since it can sleep and must not run under a spinlock.\n\nhrtimer_cancel() is always called without bcm_rx_update_lock held, since\nbcm_rx_timeout_handler()/bcm_rx_thr_handler() take the same lock and a\nrunning callback would otherwise deadlock against the canceller.\n\nAlso close a related race: bcm_rx_setup() cleared the RTR flag in the\nstored reply frame\u0027s can_id as a separate, unprotected step after the\nframe content was already installed, so a concurrent bcm_rx_handler()\ncould transmit a stale reply with CAN_RTR_FLAG still set. Fold that\nnormalization into the initial frame preparation instead (on the staged\nbuffer for updates, directly on op-\u003eframes pre-registration for new\nops), so the installed frame is always atomically self-consistent.\n\nbcm_rx_handler()\u0027s RX_RTR_FRAME check now takes a lock-protected\nsnapshot of op-\u003eflags before deciding whether to call bcm_can_tx(),\nbut does not hold the lock across that call.\n\nAlso take a lock-protected snapshot of the currframe in bcm_can_tx()\nto avoid partly overwrites by content updates in bcm_tx_setup().\nFinally check if a TX_RESET_MULTI_IDX/SETTIMER might have reset\nop-\u003ecurrframe between the two locked sections in bcm_can_tx().\n\nOmit calling hrtimer_forward() with zero interval in bcm_rx_thr_handler().\nkt_ival2 may have been concurrently cleared by bcm_rx_setup() before it\ncancels this timer, so check kt_ival2 inside the bcm_rx_update_lock."
    }
  ],
  "id": "CVE-2026-72121",
  "lastModified": "2026-08-19T17:20:59.160",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "ADJACENT_NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 8.8,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 2.8,
        "impactScore": 5.9,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-08-15T06:21:26.650",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/19b1994069dd29478ba767de1f98f14a088198dc"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/749179c2e25b95d22499ed29096b3e02d6dfd2b4"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/834cbca3b12e46887f7a9b35f1981a888360ea4c"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/96994180bd7b248b0cc698afe926e23fc1bda59b"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/a7c369e7da8203e2b5be12bbcac7b9ab2ed5b658"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/a7eb6db1cd3f7b556a301dc1265945ad112089f7"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/caa8704a7f3cb7806331596195385437126ecb3a"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/fc9f5ee1b073bd233d9c604e338af4ebb42cbc33"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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