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CVE Record

CVE-2024-42235: s390/mm: Add NULL pointer check to crst_table_free() base_crst_free()

In the Linux kernel, the following vulnerability has been resolved: s390/mm: Add NULL pointer check to crst_table_free() base_crst_free() crst_table_free() used to work with NULL pointers before the conversion to ptdescs. Since crst_table_free() can be called with a NULL pointer (error handling in crst_table_upgrade() add an explicit check. Also add the same check to base_crst_free() for consistency reasons. In real life this should not happen, since order two GFP_KERNEL allocations will not fail, unless FAIL_PAGE_ALLOC is enabled and used.

HighCVSS 7.8Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

This Linux kernel flaw affects s390 memory-management error handling. A missing NULL-pointer check could crash or corrupt the kernel if a page-table allocation fails. The source says this is unlikely in normal operation and is mainly expected when allocation-failure testing is enabled, reducing practical urgency despite the high CVSS score.

Executive priority

Prioritize affected s390 systems through normal high-severity kernel patching, especially multi-user or locally accessible hosts. Emergency action is not supported by the supplied evidence because active exploitation is unreported and the vulnerable condition is described as operationally unlikely. Confirm exposure before escalating broader response.

Technical view

After conversion to ptdescs, crst_table_free() no longer safely accepted NULL during crst_table_upgrade() error handling. The fix adds explicit NULL checks to crst_table_free() and base_crst_free(). CVSS 3.1 is 7.8, requiring local access and low privileges, with potentially high confidentiality, integrity, and availability impact.

Likely exposure

Exposure appears limited to affected Linux kernels running on the s390 architecture. The supplied affected-version data includes 6.6, 6.6.41, 6.9.10, and 6.10 but does not provide reliable version-range semantics. Normal systems are unlikely to reach the vulnerable path unless allocation-failure injection is enabled.

Exploitation context

The CVE is not listed in CISA KEV within the supplied bundle, and no source reports active exploitation. Triggering requires local access and an unusual allocation failure during page-table upgrade handling. The kernel description says this should not occur in real life unless FAIL_PAGE_ALLOC is enabled and used.

Researcher notes

The practical trigger depends on crst_table_upgrade() reaching error cleanup with a NULL allocation result. The upstream explanation considers order-two GFP_KERNEL allocation failure unrealistic without FAIL_PAGE_ALLOC. The supplied records do not establish exploitability beyond CVSS assumptions, affected version boundaries are ambiguous, and no CWE is provided.

Mitigation direction

  • Identify Linux systems using the s390 architecture and record their running kernel versions.
  • Install a vendor-supported kernel containing the referenced NULL-check fix, following distribution guidance.
  • Reboot into the corrected kernel after applying the update.
  • If an update is unavailable, consult the Linux distribution vendor for supported mitigation guidance.
  • Avoid enabling allocation-failure injection on production systems unless operationally required.

Validation and detection

  • Confirm each assessed system uses s390 rather than another architecture.
  • Compare the running kernel package against the distribution's CVE advisory or changelog.
  • Verify the deployed source includes the referenced crst_table_free() NULL-check correction.
  • After reboot, confirm the corrected kernel is the active kernel.
  • Determine whether FAIL_PAGE_ALLOC fault injection is enabled or used in production.
Prepared
Confidence
high
Sources
5

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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CVE-2024-42235 mapping review

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Vulnerability profileCVE Program record
Severity
High
CVSS
7.8 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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
1ADP providers
4Source 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
7.8CVSS 3.1HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H1.85.9Linux

Vulnerability scoring details

Base CVSS 3.1 score

7.8High
CVSS 3.1 vector shape for CVE-2024-42235Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

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

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux6326c26c1514757242829b292b26eac589013200, 6326c26c1514757242829b292b26eac589013200, 6326c26c1514757242829b292b26eac589013200unaffected
LinuxLinux6.6, 0, 6.6.41, 6.9.10, 6.10affected
Weakness

CWE details

No CWE listed

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