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CVE Record

CVE-2024-42233: filemap: replace pte_offset_map() with pte_offset_map_nolock()

In the Linux kernel, the following vulnerability has been resolved: filemap: replace pte_offset_map() with pte_offset_map_nolock() The vmf->ptl in filemap_fault_recheck_pte_none() is still set from handle_pte_fault(). But at the same time, we did a pte_unmap(vmf->pte). After a pte_unmap(vmf->pte) unmap and rcu_read_unlock(), the page table may be racily changed and vmf->ptl maybe fails to protect the actual page table. Fix this by replacing pte_offset_map() with pte_offset_map_nolock(). As David said, the PTL pointer might be stale so if we continue to use it infilemap_fault_recheck_pte_none(), it might trigger UAF. Also, if the PTL fails, the issue fixed by commit 58f327f2ce80 ("filemap: avoid unnecessary major faults in filemap_fault()") might reappear.

HighCVSS 7.8Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

A Linux kernel race can leave the file-mapping fault handler using an outdated page-table lock. This may cause a use-after-free, potentially allowing a low-privileged local attacker to crash the system or compromise data and system integrity. Remote exploitation is not indicated by the supplied CVSS vector.

Executive priority

Treat this as an expedited kernel-maintenance issue, especially on shared, multi-user, development, hosting, or workload-execution systems. It is high severity but requires local low-privileged access, and the supplied evidence does not show active exploitation. Resolve version ambiguity quickly and deploy supported fixed kernels through normal emergency-change controls.

Technical view

After pte_unmap() and RCU unlock, the page table may change while vmf->ptl still references the previous lock. filemap_fault_recheck_pte_none() can consequently operate with stale protection and trigger a use-after-free. The upstream correction replaces pte_offset_map() with pte_offset_map_nolock() so the current page-table lock is obtained.

Likely exposure

Exposure is limited to Linux systems running an affected kernel and reachable by a low-privileged local user or process. The bundle references 6.9, 6.9.10, and 6.10, but its flattened version data does not clearly distinguish affected and fixed boundaries. Confirm exact exposure through distributor advisories and backport records.

Exploitation context

The supplied CVSS assessment is 7.8: local access, low privileges, low complexity, no user interaction, and potentially high confidentiality, integrity, and availability impact. The CVE is not listed as KEV in the bundle, and no supplied source establishes public or active exploitation.

Researcher notes

The central condition is lock validity across pte_unmap() and RCU unlock, not merely a missing lock. A concurrent page-table change can make vmf->ptl stale, undermining protection in filemap_fault_recheck_pte_none(). The fix commits should be examined when determining whether vendor kernels contain an equivalent backport.

Mitigation direction

  • Apply a vendor-supported kernel update containing the applicable upstream fix, then reboot into the updated kernel.
  • Prioritize hosts allowing local users or untrusted workloads, consistent with the local, low-privilege attack vector.
  • Restrict local access and untrusted workload execution until affected systems are updated.
  • Check vendor guidance for exact fixed builds because the bundle's version boundaries are ambiguous.

Validation and detection

  • Confirm the exact running kernel release and distributor build on every Linux host.
  • Map each build to distributor advisories or backport records for CVE-2024-42233.
  • Verify the applicable fix is present in the deployed kernel source or package changelog.
  • Confirm systems booted into the updated kernel after installation.
  • Review kernel crashes for page-table or use-after-free symptoms; their absence does not establish safety.
Prepared
Confidence
medium
Sources
4

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-2024-42233 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
3Source 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-2024-42233Attack 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
LinuxLinux58f327f2ce80f9c7b4a70e9cf017ae8810d44a20, 58f327f2ce80f9c7b4a70e9cf017ae8810d44a20unaffected
LinuxLinux6.9, 0, 6.9.10, 6.10affected
Weakness

CWE details

No CWE listed

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