CVE-2026-72124 (GCVE-0-2026-72124)
Vulnerability from cvelistv5
Published
2026-08-15 05:53
Modified
2026-08-19 16:36
Severity ?
VLAI Severity ?
EPSS score ?
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superseded.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 | ||
|---|---|---|---|---|
| Linux | Linux |
Version: e057dd3fc20ffb3d7f150af46542a51b59b90127 Version: e057dd3fc20ffb3d7f150af46542a51b59b90127 Version: e057dd3fc20ffb3d7f150af46542a51b59b90127 Version: e057dd3fc20ffb3d7f150af46542a51b59b90127 Version: e057dd3fc20ffb3d7f150af46542a51b59b90127 Version: e057dd3fc20ffb3d7f150af46542a51b59b90127 Version: e057dd3fc20ffb3d7f150af46542a51b59b90127 Version: e057dd3fc20ffb3d7f150af46542a51b59b90127 |
||
{
"containers": {
"cna": {
"affected": [
{
"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": [
{
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"version": "e057dd3fc20ffb3d7f150af46542a51b59b90127",
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},
{
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},
{
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},
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}
]
},
{
"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"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "5.10.265",
"versionStartIncluding": "5.10",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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"vulnerable": true
},
{
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{
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},
{
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},
{
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}
],
"negate": false,
"operator": "OR"
}
]
}
],
"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."
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 8.8,
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"scenarios": [
{
"lang": "en",
"value": "AV:A - The bug is hit on the SocketCAN receive path (can_rcv\u2192isotp_rcv/isotp_rcv_echo for FC/echo frames) racing sendmsg() and hrtimers; in automotive/industrial ISO-TP (UDS) deployments an attacker on the same CAN segment can inject timed FC/echo frames without host shell access.\nAC:L - The attacker controls both sides of the race via concurrent sendmsg()/close() threads plus crafted FC/echo traffic and timer timing; sashiko-bot/syzkaller reproduces it reliably with no conditions outside attacker influence.\nPR:N - Once a victim ISO-TP socket is bound and transmitting (normal diagnostic behavior), an unauthenticated CAN bus peer needs no Linux credentials; CAN_ISOTP socket create/bind/sendmsg paths impose no capability checks.\nUI:N - No victim interaction beyond routine background ISO-TP traffic on an already-bound socket; the attacker drives concurrent transfers and FC/echo timing to hit the unsynchronized TX state transitions.\nS:U - Impact is kernel ISO-TP/socket heap corruption within the same OS security authority, without inherent VM escape, container breakout, or IOMMU boundary crossing.\nC:H - Mis-serialized so-\u003etx.state, tx.idx, and rx reassembly state lets stale echo/FC/timer handlers operate on the wrong transfer, enabling out-of-bounds reads from tpcon tx/rx buffers and adjacent kernel heap disclosure.\nI:H - The same cross-transfer corruption writes through tpcon buffers and socket state (indices, sequence numbers, timers), yielding attacker-influenced kernel heap corruption rather than a benign protocol error.\nA:H - Stale timers and handlers acting on superseded transfers can provoke sk_err storms, skb/state corruption, and kernel oops/panic in softirq/timer context, matching prior isotp timer race failures and repeatable DoS."
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-19T16:36:21.129Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/bbedeb67a9a684f2fb78c55bd3662c400526715e"
},
{
"url": "https://git.kernel.org/stable/c/377a8f500704da42ed86a4541ed930e9dcfdb2ea"
},
{
"url": "https://git.kernel.org/stable/c/6da8119e8dd542194103139812d1a4b7dcd1aedd"
},
{
"url": "https://git.kernel.org/stable/c/0b05eca9589f609e2491b528dccf683168a4cda8"
},
{
"url": "https://git.kernel.org/stable/c/a7d90e7b5e75d7406c889fe36e9a61ee364a00cb"
},
{
"url": "https://git.kernel.org/stable/c/37beb16e08cae94cc05840c7274225e3b0b38ae7"
},
{
"url": "https://git.kernel.org/stable/c/4f1fdf1a1c317bcac0c6b6c8e12642c9983de1ca"
},
{
"url": "https://git.kernel.org/stable/c/cf070fe33bfbd1a4c21236078fadb35dd223a157"
}
],
"title": "can: isotp: serialize TX state transitions under so-\u003erx_lock",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-72124",
"datePublished": "2026-08-15T05:53:02.172Z",
"dateReserved": "2026-08-09T03:40:39.907Z",
"dateUpdated": "2026-08-19T16:36:21.129Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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