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CVE Record

CVE-2021-47455: ptp: Fix possible memory leak in ptp_clock_register()

In the Linux kernel, the following vulnerability has been resolved: ptp: Fix possible memory leak in ptp_clock_register() I got memory leak as follows when doing fault injection test: unreferenced object 0xffff88800906c618 (size 8): comm "i2c-idt82p33931", pid 4421, jiffies 4294948083 (age 13.188s) hex dump (first 8 bytes): 70 74 70 30 00 00 00 00 ptp0.... backtrace: [<00000000312ed458>] __kmalloc_track_caller+0x19f/0x3a0 [<0000000079f6e2ff>] kvasprintf+0xb5/0x150 [<0000000026aae54f>] kvasprintf_const+0x60/0x190 [<00000000f323a5f7>] kobject_set_name_vargs+0x56/0x150 [<000000004e35abdd>] dev_set_name+0xc0/0x100 [<00000000f20cfe25>] ptp_clock_register+0x9f4/0xd30 [ptp] [<000000008bb9f0de>] idt82p33_probe.cold+0x8b6/0x1561 [ptp_idt82p33] When posix_clock_register() returns an error, the name allocated in dev_set_name() will be leaked, the put_device() should be used to give up the device reference, then the name will be freed in kobject_cleanup() and other memory will be freed in ptp_clock_release().

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysislow

Security readout for executives and security teams

Plain-English summary

This is a Linux kernel memory leak in the Precision Time Protocol clock registration path. If registration fails, allocated device-name memory may not be released. The public record shows it was found by fault injection, not real-world attacks.

Executive priority

Treat this as a low-urgency kernel maintenance item unless PTP-enabled systems are stability-sensitive. Patch through normal kernel update cycles, with higher attention for infrastructure depending on precise time synchronization.

Technical view

In ptp_clock_register(), an error returned from posix_clock_register() could bypass the correct device cleanup path. The fix uses put_device() so kobject_cleanup() and ptp_clock_release() free the device name and related memory.

Likely exposure

Exposure is most relevant to Linux systems using the kernel PTP clock subsystem or related PTP hardware clock drivers. The CVE record lists Linux kernel versions and stable commit identifiers, but the source bundle does not provide a complete distribution-by-distribution affected matrix.

Exploitation context

The source bundle provides no evidence of active exploitation, and the CVE is not marked KEV. The reported trigger came from fault injection testing during PTP driver probing, so practical attacker reachability is unclear from the available sources.

Researcher notes

Evidence supports a cleanup bug in an error path, not a demonstrated exploit primitive. The available bundle lacks CVSS, CWE, attacker requirements, and complete fixed-version mapping, so validation should focus on kernel provenance and downstream vendor advisories.

Mitigation direction

  • Update to a vendor kernel containing the referenced stable fixes.
  • For Debian systems, review the cited Debian LTS advisory.
  • Prioritize systems using PTP hardware clock drivers.
  • Check vendor guidance for exact fixed package versions.
  • Monitor kernel advisories for downstream backports.

Validation and detection

  • Inventory Linux kernel versions on systems using PTP clock functionality.
  • Check whether PTP hardware clock drivers are loaded or configured.
  • Confirm installed kernels include the referenced stable fix commits or vendor backports.
  • Review kernel logs for PTP driver registration failures if investigating leaks.
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

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ATT&CK lookup starting points

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CVE-2021-47455 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

CISA-ADPCISA ADP Vulnrichment
other:ssvc
CVECVE Program Container

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinuxa33121e5487b424339636b25c35d3a180eaa5f5e, a33121e5487b424339636b25c35d3a180eaa5f5e, a33121e5487b424339636b25c35d3a180eaa5f5e, 5230ef61882d2d14deb846eb6b48370694816e4c, 6f5e3bb7879ee1eb71c6c3cbaaffbb0da6cd7d57, 89e8fc989feaac00bf1a7f9a766289422e2f5768, 2dece4d6d13fe179ee3a5991811712725a56e2f7, 0393b8720128d5b39db8523e5bfbfc689f18c37c, bfa2e0cd3dfda64fde43c3dca3aeba298d2fe7adunaffected
LinuxLinux5.5, 0, 5.10.241, 5.14.15, 5.15affected
Weakness

CWE details

No CWE listed

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