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CVE Record

CVE-2021-47176: s390/dasd: add missing discipline function

In the Linux kernel, the following vulnerability has been resolved: s390/dasd: add missing discipline function Fix crash with illegal operation exception in dasd_device_tasklet. Commit b72949328869 ("s390/dasd: Prepare for additional path event handling") renamed the verify_path function for ECKD but not for FBA and DIAG. This leads to a panic when the path verification function is called for a FBA or DIAG device. Fix by defining a wrapper function for dasd_generic_verify_path().

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

CVE-2021-47176 is a Linux kernel s390 DASD bug that can crash affected systems. It affects specialized IBM Z/Linux storage handling, not typical x86 servers. The known impact is availability: a kernel panic when path verification is called for FBA or DIAG DASD devices.

Executive priority

Treat this as a targeted availability risk for IBM Z/Linux environments. It is not broad internet-exposed urgency, but affected production mainframe workloads should be patched through normal kernel maintenance because a storage-path bug can cause service interruption.

Technical view

A Linux s390 DASD change renamed the ECKD verify_path function but missed equivalent FBA and DIAG discipline handling. When dasd_device_tasklet invokes path verification for those devices, the missing function path can trigger an illegal operation exception and panic. The fix adds a wrapper for dasd_generic_verify_path().

Likely exposure

Exposure is likely limited to Linux systems on s390/s390x using DASD FBA or DIAG devices. General Linux fleets without this architecture and storage stack are unlikely to be affected. Exact exposure depends on kernel build, distro backports, and whether the referenced stable fixes are present.

Exploitation context

The source bundle does not report active exploitation, public exploit activity, or KEV listing. The described failure is a crash condition in kernel storage-path handling, so business risk is primarily unplanned outage on affected mainframe Linux workloads.

Researcher notes

The CVE record lacks CVSS, CWE, exploit details, and distro-specific fixed version mapping. The affected version data in the bundle is commit and release based, so validate against actual downstream kernel source or vendor changelogs before declaring systems fixed or vulnerable.

Mitigation direction

  • Check vendor kernel advisories for CVE-2021-47176 and s390 DASD fixes.
  • Update affected systems to a kernel containing the referenced stable commits.
  • Prioritize IBM Z/Linux hosts using DASD FBA or DIAG devices.
  • Use vendor-supported maintenance channels instead of manually cherry-picking kernel patches.
  • Plan reboot or failover windows for kernel updates on production systems.

Validation and detection

  • Inventory Linux hosts running on s390 or s390x architecture.
  • Identify systems using DASD FBA or DIAG device disciplines.
  • Compare running kernel packages against vendor advisories and fixed builds.
  • Confirm whether the referenced stable commits are included in deployed kernels.
  • Review crash logs for illegal operation exceptions in dasd_device_tasklet.
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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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
LinuxLinux8bc5a76268fb334236296b4c185b8337e0d85473, 72aebdac390bf0dc04c0385d2db7ee522f4ffa3c, b72949328869dfd45f6452c2410647afd7db5f1a, b72949328869dfd45f6452c2410647afd7db5f1aunaffected
LinuxLinux5.11, 0, 5.4.237, 5.10.175, 5.12.9, 5.13affected
Weakness

CWE details

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