FKIE_CVE-2026-72124
Vulnerability from fkie_nvd - Published: 2026-08-15 06:21 - Updated: 2026-08-19 17:20
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved:
can: isotp: serialize TX state transitions under so->rx_lock
The TX state machine (so->tx.state) is driven from three contexts:
sendmsg() claiming and progressing a transfer, the RX path consuming
Flow Control/echo frames, and two hrtimers timing out a stalled
transfer. Mixing a lock-free cmpxchg() claim in sendmsg() with
hrtimer_cancel() calls made under so->rx_lock elsewhere left windows
where a frame or timer callback could act on a state that had already
moved on, corrupting an unrelated transfer.
so->rx_lock now covers the full lifecycle of a TX claim: sendmsg()
takes it to check so->tx.state is ISOTP_IDLE, switch it to
ISOTP_SENDING, bump so->tx_gen and drain the previous transfer's
timers - all as one critical section. isotp_rcv_fc()/isotp_rcv_cf()
already run under this lock via isotp_rcv(), and isotp_rcv_echo() now
takes it itself, so none of them can ever observe a transfer mid-claim.
This also means a transfer can no longer be handed to sendmsg()'s
cleanup paths (signal or send error) while another thread is
concurrently claiming or finishing it, so those paths can cancel
timers and reset the state unconditionally.
isotp_release() claims the socket the same way, so a racing sendmsg()
sees a consistent ISOTP_SHUTDOWN and skips arming its timer or sending.
Only the hrtimer callbacks stay outside so->rx_lock, since they run
under so->rx_lock's cancellation elsewhere and taking it themselves
would deadlock. so->tx_gen lets them recognize whether the transfer
they timed out is still the one currently active, so they don't
report an error against a transfer that has since completed or been
superseded.
References
Impacted products
| Vendor | Product | Version |
|---|
{
"affected": [
{
"affectedData": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"net/can/isotp.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "bbedeb67a9a684f2fb78c55bd3662c400526715e",
"status": "affected",
"version": "e057dd3fc20ffb3d7f150af46542a51b59b90127",
"versionType": "git"
},
{
"lessThan": "377a8f500704da42ed86a4541ed930e9dcfdb2ea",
"status": "affected",
"version": "e057dd3fc20ffb3d7f150af46542a51b59b90127",
"versionType": "git"
},
{
"lessThan": "6da8119e8dd542194103139812d1a4b7dcd1aedd",
"status": "affected",
"version": "e057dd3fc20ffb3d7f150af46542a51b59b90127",
"versionType": "git"
},
{
"lessThan": "0b05eca9589f609e2491b528dccf683168a4cda8",
"status": "affected",
"version": "e057dd3fc20ffb3d7f150af46542a51b59b90127",
"versionType": "git"
},
{
"lessThan": "a7d90e7b5e75d7406c889fe36e9a61ee364a00cb",
"status": "affected",
"version": "e057dd3fc20ffb3d7f150af46542a51b59b90127",
"versionType": "git"
},
{
"lessThan": "37beb16e08cae94cc05840c7274225e3b0b38ae7",
"status": "affected",
"version": "e057dd3fc20ffb3d7f150af46542a51b59b90127",
"versionType": "git"
},
{
"lessThan": "4f1fdf1a1c317bcac0c6b6c8e12642c9983de1ca",
"status": "affected",
"version": "e057dd3fc20ffb3d7f150af46542a51b59b90127",
"versionType": "git"
},
{
"lessThan": "cf070fe33bfbd1a4c21236078fadb35dd223a157",
"status": "affected",
"version": "e057dd3fc20ffb3d7f150af46542a51b59b90127",
"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"net/can/isotp.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "5.10"
},
{
"lessThan": "5.10",
"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": "6.18.40",
"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: isotp: serialize TX state transitions under so-\u003erx_lock\n\nThe TX state machine (so-\u003etx.state) is driven from three contexts:\nsendmsg() claiming and progressing a transfer, the RX path consuming\nFlow Control/echo frames, and two hrtimers timing out a stalled\ntransfer. Mixing a lock-free cmpxchg() claim in sendmsg() with\nhrtimer_cancel() calls made under so-\u003erx_lock elsewhere left windows\nwhere a frame or timer callback could act on a state that had already\nmoved on, corrupting an unrelated transfer.\n\nso-\u003erx_lock now covers the full lifecycle of a TX claim: sendmsg()\ntakes it to check so-\u003etx.state is ISOTP_IDLE, switch it to\nISOTP_SENDING, bump so-\u003etx_gen and drain the previous transfer\u0027s\ntimers - all as one critical section. isotp_rcv_fc()/isotp_rcv_cf()\nalready run under this lock via isotp_rcv(), and isotp_rcv_echo() now\ntakes it itself, so none of them can ever observe a transfer mid-claim.\nThis also means a transfer can no longer be handed to sendmsg()\u0027s\ncleanup paths (signal or send error) while another thread is\nconcurrently claiming or finishing it, so those paths can cancel\ntimers and reset the state unconditionally.\n\nisotp_release() claims the socket the same way, so a racing sendmsg()\nsees a consistent ISOTP_SHUTDOWN and skips arming its timer or sending.\n\nOnly the hrtimer callbacks stay outside so-\u003erx_lock, since they run\nunder so-\u003erx_lock\u0027s cancellation elsewhere and taking it themselves\nwould deadlock. so-\u003etx_gen lets them recognize whether the transfer\nthey timed out is still the one currently active, so they don\u0027t\nreport an error against a transfer that has since completed or been\nsuperseded."
}
],
"id": "CVE-2026-72124",
"lastModified": "2026-08-19T17:20:59.847",
"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": "2026-08-15T06:21:29.720",
"references": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/0b05eca9589f609e2491b528dccf683168a4cda8"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/377a8f500704da42ed86a4541ed930e9dcfdb2ea"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/37beb16e08cae94cc05840c7274225e3b0b38ae7"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/4f1fdf1a1c317bcac0c6b6c8e12642c9983de1ca"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/6da8119e8dd542194103139812d1a4b7dcd1aedd"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/a7d90e7b5e75d7406c889fe36e9a61ee364a00cb"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/bbedeb67a9a684f2fb78c55bd3662c400526715e"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/cf070fe33bfbd1a4c21236078fadb35dd223a157"
}
],
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Received"
}
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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