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CVE Record

CVE-2021-47186: tipc: check for null after calling kmemdup

In the Linux kernel, the following vulnerability has been resolved: tipc: check for null after calling kmemdup kmemdup can return a null pointer so need to check for it, otherwise the null key will be dereferenced later in tipc_crypto_key_xmit as can be seen in the trace [1]. [1] https://syzkaller.appspot.com/bug?id=bca180abb29567b189efdbdb34cbf7ba851c2a58

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

CVE-2021-47186 is a Linux kernel TIPC bug where memory allocation failure was not checked before later use. In practical terms, a vulnerable kernel could hit a null-pointer dereference in this subsystem, likely causing a kernel fault or denial of service. The source bundle provides no CVSS score and no evidence of active exploitation.

Executive priority

Handle through normal kernel vulnerability management unless TIPC is enabled on critical systems. There is no supplied evidence of active exploitation or severity scoring, but kernel faults can affect availability and should not be ignored.

Technical view

The Linux kernel TIPC crypto path called kmemdup and later dereferenced the resulting key in tipc_crypto_key_xmit without validating allocation success. The kernel stable fixes add the missing null check. Evidence points to a syzkaller-discovered crash trace, not a disclosed exploit chain.

Likely exposure

Exposure is limited to systems running affected Linux kernel versions with the vulnerable TIPC code present. The bundle lists Linux kernel version data around 5.10, 5.10.82, 5.15.5, and 5.16, but distro backports may change actual status.

Exploitation context

The CVE is not listed as KEV in the supplied data. The sources do not describe exploitation in the wild, exploit prerequisites, authentication requirements, or remote reachability. Treat exploitation context as incomplete until vendor or distribution advisories clarify affected configurations.

Researcher notes

The key evidence is an upstream Linux kernel fix for an unchecked kmemdup result before tipc_crypto_key_xmit. The public description is sparse: no CVSS, CWE, attack vector, or exploitability analysis is provided. Validate against exact downstream kernel patches.

Mitigation direction

  • Check your Linux distribution advisory for CVE-2021-47186 status.
  • Update kernels to versions containing the referenced stable fixes.
  • Prioritize systems where TIPC is enabled or kernel availability is critical.
  • Track vendor backports instead of relying only on upstream version numbers.

Validation and detection

  • Inventory Linux kernel versions across servers, appliances, and containers hosts.
  • Check whether TIPC support is built, loaded, or enabled.
  • Compare installed kernel packages against distro CVE advisories.
  • Confirm patch presence using vendor package changelogs or upstream stable commits.
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-2021-47186 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: yesTechnical 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
LinuxLinux1ef6f7c9390ff5308c940ff8d0a53533a4673ad9, 1ef6f7c9390ff5308c940ff8d0a53533a4673ad9, 1ef6f7c9390ff5308c940ff8d0a53533a4673ad9unaffected
LinuxLinux5.10, 0, 5.10.82, 5.15.5, 5.16affected
Weakness

CWE details

No CWE listed

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