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CVE Record

CVE-2023-52704: freezer,umh: Fix call_usermode_helper_exec() vs SIGKILL

In the Linux kernel, the following vulnerability has been resolved: freezer,umh: Fix call_usermode_helper_exec() vs SIGKILL Tetsuo-San noted that commit f5d39b020809 ("freezer,sched: Rewrite core freezer logic") broke call_usermodehelper_exec() for the KILLABLE case. Specifically it was missed that the second, unconditional, wait_for_completion() was not optional and ensures the on-stack completion is unused before going out-of-scope.

MediumCVSS 5.5Not KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

This is a Linux kernel availability issue. A local, low-privileged actor may be able to trigger a crash or hang condition related to usermode helper execution and SIGKILL handling. The source bundle does not show data theft or privilege escalation impact.

Executive priority

Address through normal kernel patch management, with higher urgency for shared servers or container hosts. This is not evidenced as remotely exploitable or actively exploited, but availability impact can matter operationally.

Technical view

The bug is in Linux freezer/usermode-helper handling after commit f5d39b020809. For KILLABLE usermode helper execution, required completion waiting was missed, allowing an on-stack completion object to go out of scope too early. CVSS rates impact as local, low-complexity, low-privilege, availability-only.

Likely exposure

Exposure is most relevant on Linux systems running affected 6.1 or 6.2-era kernels, or kernels carrying commit f5d39b020809 without the linked stable fixes.

Exploitation context

No KEV listing is provided, and the source bundle does not cite active exploitation or public weaponization. Treat this as a local denial-of-service risk until vendor kernel status is confirmed.

Researcher notes

The key condition is the KILLABLE path in call_usermode_helper_exec() after freezer core rewrite changes. Focus review on whether deployed kernels include the second unconditional wait_for_completion() behavior restored by the stable fixes.

Mitigation direction

  • Upgrade to a vendor kernel containing the linked stable fixes.
  • Confirm distribution advisories before applying upstream commits directly.
  • Reduce untrusted local user and container access on affected systems.
  • Prioritize multi-tenant hosts and exposed workload platforms.

Validation and detection

  • Inventory kernel versions and vendor package revisions across Linux assets.
  • Compare deployed kernels against the CVE record and linked stable commits.
  • Check vendor advisories for backported fixes with different version numbers.
  • Validate that affected 6.1 or 6.2 kernels are no longer deployed.
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

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-2023-52704 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

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Vulnerability profileCVE Program record
Severity
Medium
CVSS
5.5 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/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
2ADP 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
5.5CVSS 3.1MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H1.83.6CISA-ADP

Vulnerability scoring details

Base CVSS 3.1 score

5.5Medium
CVSS 3.1 vector shape for CVE-2023-52704Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/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
cvssV3_1other:ssvc
CVECVE Program Container

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinuxf5d39b020809146cc28e6e73369bf8065e0310aa, f5d39b020809146cc28e6e73369bf8065e0310aaunaffected
LinuxLinux6.1, 0, 6.1.13, 6.2affected
Weakness

CWE details

No CWE listed

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