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CVE Record

CVE-2021-47457: can: isotp: isotp_sendmsg(): add result check for wait_event_interruptible()

In the Linux kernel, the following vulnerability has been resolved: can: isotp: isotp_sendmsg(): add result check for wait_event_interruptible() Using wait_event_interruptible() to wait for complete transmission, but do not check the result of wait_event_interruptible() which can be interrupted. It will result in TX buffer has multiple accessors and the later process interferes with the previous process. Following is one of the problems reported by syzbot. ============================================================= WARNING: CPU: 0 PID: 0 at net/can/isotp.c:840 isotp_tx_timer_handler+0x2e0/0x4c0 CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.13.0-rc7+ #68 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1 04/01/2014 RIP: 0010:isotp_tx_timer_handler+0x2e0/0x4c0 Call Trace: <IRQ> ? isotp_setsockopt+0x390/0x390 __hrtimer_run_queues+0xb8/0x610 hrtimer_run_softirq+0x91/0xd0 ? rcu_read_lock_sched_held+0x4d/0x80 __do_softirq+0xe8/0x553 irq_exit_rcu+0xf8/0x100 sysvec_apic_timer_interrupt+0x9e/0xc0 </IRQ> asm_sysvec_apic_timer_interrupt+0x12/0x20 Add result check for wait_event_interruptible() in isotp_sendmsg() to avoid multiple accessers for tx buffer.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

CVE-2021-47457 is a Linux kernel CAN ISO-TP issue. A send path waited for transmission completion but did not handle interruption, allowing overlapping access to the transmit buffer. The public record shows a syzbot-reported kernel warning, but gives no business-impact metrics or confirmed attack activity.

Executive priority

Prioritize through normal kernel maintenance unless your environment depends on CAN ISO-TP. Escalate for automotive, embedded, test, or operational systems using Linux CAN features, because source evidence is incomplete but the bug affects kernel-level behavior.

Technical view

In net/can/isotp.c, isotp_sendmsg() used wait_event_interruptible() without checking its return. If interrupted, another process could access the TX buffer while prior transmission handling continued, interfering with state and triggering warnings in isotp_tx_timer_handler(). Kernel stable commits add the missing result check.

Likely exposure

Exposure appears limited to Linux systems running affected kernel versions where CAN ISO-TP functionality is available or used. The source bundle lists Linux/Linux as affected but does not identify distributions, appliances, containers, remote exposure, or required privileges.

Exploitation context

No CISA KEV listing is provided, and the bundle cites no active exploitation. The observed evidence is a syzbot report showing a kernel warning in a QEMU test environment. Treat exploitability and operational impact as not fully characterized from these sources.

Researcher notes

The record centers on an interruptible wait handling bug, not a fully described attack path. Key unknowns are privilege requirements, confidentiality or integrity impact, and whether the issue can be driven beyond local CAN ISO-TP use. Avoid overstating risk without vendor-specific analysis.

Mitigation direction

  • Update to a vendor kernel containing the referenced stable fixes.
  • Check Linux distribution advisories for backported fixes and affected package versions.
  • If patching is delayed, reduce unnecessary CAN ISO-TP exposure where operationally possible.
  • Track vendor guidance because the bundle provides no CVSS or workaround details.

Validation and detection

  • Inventory Linux kernel versions on systems that use CAN ISO-TP.
  • Confirm whether vendor kernel packages include the referenced stable commits.
  • Review kernel logs for CAN ISO-TP warnings or related instability.
  • Verify post-update behavior with normal CAN ISO-TP workflows in staging.
Prepared
Confidence
medium
Sources
5

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

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CVE-2021-47457 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
3Timeline events
2ADP providers
4Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: noTechnical Impact: partial

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
other:ssvc
CVECVE Program Container

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinuxe057dd3fc20ffb3d7f150af46542a51b59b90127, e057dd3fc20ffb3d7f150af46542a51b59b90127, e057dd3fc20ffb3d7f150af46542a51b59b90127unaffected
LinuxLinux5.10, 0, 5.10.76, 5.14.15, 5.15affected
Weakness

CWE details

No CWE listed

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.