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CVE Record

CVE-2021-47153: i2c: i801: Don't generate an interrupt on bus reset

In the Linux kernel, the following vulnerability has been resolved: i2c: i801: Don't generate an interrupt on bus reset Now that the i2c-i801 driver supports interrupts, setting the KILL bit in a attempt to recover from a timed out transaction triggers an interrupt. Unfortunately, the interrupt handler (i801_isr) is not prepared for this situation and will try to process the interrupt as if it was signaling the end of a successful transaction. In the case of a block transaction, this can result in an out-of-range memory access. This condition was reproduced several times by syzbot: https://syzkaller.appspot.com/bug?extid=ed71512d469895b5b34e https://syzkaller.appspot.com/bug?extid=8c8dedc0ba9e03f6c79e https://syzkaller.appspot.com/bug?extid=c8ff0b6d6c73d81b610e https://syzkaller.appspot.com/bug?extid=33f6c360821c399d69eb https://syzkaller.appspot.com/bug?extid=be15dc0b1933f04b043a https://syzkaller.appspot.com/bug?extid=b4d3fd1dfd53e90afd79 So disable interrupts while trying to reset the bus. Interrupts will be enabled again for the following transaction.

MediumCVSS 6Not KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

This is a Linux kernel driver flaw in the i2c-i801 bus controller. During recovery from a timed-out transaction, the driver could trigger an unexpected interrupt and mishandle memory. Business risk is mainly to systems where already highly privileged local users or workloads can reach this kernel path.

Executive priority

Treat as routine but real kernel maintenance risk. It is not remotely exploitable based on supplied evidence, but privileged local kernel memory bugs can matter on shared, multi-tenant, or heavily delegated systems.

Technical view

The i2c-i801 driver sets the KILL bit during bus reset after transaction timeout. With interrupt support enabled, that can invoke i801_isr, which treats the interrupt as successful transaction completion. For block transactions, the CVE states this can cause out-of-range memory access.

Likely exposure

Exposure is limited to Linux systems running affected kernel versions with the i2c-i801 driver path present. The source lists Linux kernel ranges and stable commits, but distribution backport status must be verified per vendor package.

Exploitation context

No active exploitation is cited, and KEV is false. The issue was reproduced by syzbot. CVSS marks attack vector local, low complexity, no user interaction, and high privileges required, with possible confidentiality and availability impact.

Researcher notes

Evidence supports a driver interrupt-handling bug fixed by disabling interrupts during bus reset. The source bundle does not provide public exploit details, distribution-specific affected package names, or a named workaround beyond applying fixed kernel changes.

Mitigation direction

  • Update to a vendor kernel containing the referenced stable Linux fixes.
  • Check distribution advisories for backported i2c-i801 fixes.
  • Prioritize hosts that permit privileged local users or privileged workloads.
  • If patching is delayed, follow vendor guidance on driver exposure or workarounds.

Validation and detection

  • Inventory running kernel versions across Linux assets.
  • Confirm whether affected systems load or depend on the i2c-i801 driver.
  • Review kernel package changelogs for the referenced stable commits.
  • Track remediation through normal vulnerability management until patched packages are deployed.
Prepared
Confidence
high
Sources
10

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-2021-47153 mapping review

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Vulnerability profileCVE Program record
Severity
Medium
CVSS
6 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:H

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.

1CVSS vectors
3Timeline events
2ADP providers
9Source links

SSVC decision data

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

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
6CVSS 3.1MediumCVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:H0.85.2CISA-ADP

Vulnerability scoring details

Base CVSS 3.1 score

6Medium
CVSS 3.1 vector shape for CVE-2021-47153Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:H

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

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
cvssV3_1other:ssvc
CVECVE Program Container

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux636752bcb5177a301d0266270661581de8624828, 636752bcb5177a301d0266270661581de8624828, 636752bcb5177a301d0266270661581de8624828, 636752bcb5177a301d0266270661581de8624828, 636752bcb5177a301d0266270661581de8624828, 636752bcb5177a301d0266270661581de8624828, 636752bcb5177a301d0266270661581de8624828, 636752bcb5177a301d0266270661581de8624828unaffected
LinuxLinux3.6, 0, 4.4.271, 4.9.271, 4.14.235, 4.19.193, 5.4.124, 5.10.42, 5.12.9, 5.13affected
Weakness

CWE details

No CWE listed

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