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CVE Record

CVE-2020-36784: i2c: cadence: fix reference leak when pm_runtime_get_sync fails

In the Linux kernel, the following vulnerability has been resolved: i2c: cadence: fix reference leak when pm_runtime_get_sync fails The PM reference count is not expected to be incremented on return in functions cdns_i2c_master_xfer and cdns_reg_slave. However, pm_runtime_get_sync will increment pm usage counter even failed. Forgetting to putting operation will result in a reference leak here. Replace it with pm_runtime_resume_and_get to keep usage counter balanced.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

This CVE describes a Linux kernel driver bug in the Cadence I2C controller. A failed power-management resume path can leave a reference count unbalanced, creating a leak. The provided sources do not assign CVSS severity or confirm active exploitation, so urgency depends on whether exposed systems use this driver and affected kernel builds.

Executive priority

Monitor and patch through normal kernel maintenance unless your environment depends on Cadence I2C hardware in affected Linux builds. There is no source-backed evidence of active exploitation or severe impact, but embedded and appliance fleets should verify exposure.

Technical view

In cdns_i2c_master_xfer and cdns_reg_slave, pm_runtime_get_sync can increment the PM usage counter even when it fails. Without the matching put operation, the Cadence I2C driver can leak a runtime PM reference. Kernel fixes replace that call with pm_runtime_resume_and_get to keep the counter balanced.

Likely exposure

Most relevant to Linux systems, especially embedded or SoC-based platforms, that include and use the Cadence I2C driver on affected kernel versions or vendor-derived kernels. Generic servers without this hardware or driver in use are less likely to be exposed.

Exploitation context

The source bundle does not show KEV listing, public exploit activity, exploit code, or a confirmed attack path. The evidence supports a kernel reliability/resource-management flaw, not remote compromise. Security teams should treat exploitation status as unconfirmed.

Researcher notes

The record is sparse: no CVSS, CWE, exploit evidence, or detailed impact statement is provided. The technical issue is a runtime PM reference leak on failure paths in the Cadence I2C driver. Validation should focus on code lineage and whether the driver is reachable on deployed hardware.

Mitigation direction

  • Update to a vendor-supported kernel containing the referenced stable fixes.
  • Check distribution or device-vendor advisories for backported fixes.
  • Prioritize platforms using Cadence I2C hardware or derived SoC kernels.
  • Track any vendor-specific operational mitigations if immediate patching is unavailable.

Validation and detection

  • Inventory kernel versions and vendor kernel branches on relevant Linux systems.
  • Confirm whether the Cadence I2C driver is built, loaded, or required.
  • Compare deployed kernel source against the referenced stable fix commits.
  • Review vendor release notes for CVE-2020-36784 backport status.
Prepared
Confidence
medium
Sources
6

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.

ATT&CK lookup starting points

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CVE-2020-36784 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
5Source 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

CVECVE Program Container
CISA-ADPCISA ADP Vulnrichment
other:ssvc

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux7fa32329ca03148fb2c07b4ef3247b8fc0488d6a, 7fa32329ca03148fb2c07b4ef3247b8fc0488d6a, 7fa32329ca03148fb2c07b4ef3247b8fc0488d6a, 7fa32329ca03148fb2c07b4ef3247b8fc0488d6aunaffected
LinuxLinux4.5, 0, 5.10.37, 5.11.21, 5.12.4, 5.13affected
Weakness

CWE details

No CWE listed

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