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CVE Record

CVE-2023-52879: tracing: Have trace_event_file have ref counters

In the Linux kernel, the following vulnerability has been resolved: tracing: Have trace_event_file have ref counters The following can crash the kernel: # cd /sys/kernel/tracing # echo 'p:sched schedule' > kprobe_events # exec 5>>events/kprobes/sched/enable # > kprobe_events # exec 5>&- The above commands: 1. Change directory to the tracefs directory 2. Create a kprobe event (doesn't matter what one) 3. Open bash file descriptor 5 on the enable file of the kprobe event 4. Delete the kprobe event (removes the files too) 5. Close the bash file descriptor 5 The above causes a crash! BUG: kernel NULL pointer dereference, address: 0000000000000028 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: 0000 [#1] PREEMPT SMP PTI CPU: 6 PID: 877 Comm: bash Not tainted 6.5.0-rc4-test-00008-g2c6b6b1029d4-dirty #186 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014 RIP: 0010:tracing_release_file_tr+0xc/0x50 What happens here is that the kprobe event creates a trace_event_file "file" descriptor that represents the file in tracefs to the event. It maintains state of the event (is it enabled for the given instance?). Opening the "enable" file gets a reference to the event "file" descriptor via the open file descriptor. When the kprobe event is deleted, the file is also deleted from the tracefs system which also frees the event "file" descriptor. But as the tracefs file is still opened by user space, it will not be totally removed until the final dput() is called on it. But this is not true with the event "file" descriptor that is already freed. If the user does a write to or simply closes the file descriptor it will reference the event "file" descriptor that was just freed, causing a use-after-free bug. To solve this, add a ref count to the event "file" descriptor as well as a new flag called "FREED". The "file" will not be freed until the last reference is released. But the FREE flag will be set when the event is removed to prevent any more modifications to that event from happening, even if there's still a reference to the event "file" descriptor.

HighCVSS 7.8Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

A local user may trigger a Linux kernel memory-lifecycle flaw in tracing by keeping an event file open while deleting its kprobe event. The demonstrated outcome is a kernel crash, threatening system availability. The CVSS assessment also indicates possible confidentiality and integrity impact, but the supplied evidence does not demonstrate those outcomes.

Executive priority

Treat as a high-priority local denial-of-service risk, especially on shared Linux hosts and availability-sensitive systems. Patch through normal emergency or accelerated kernel maintenance after vendor applicability confirmation. Escalate faster where untrusted users can reach tracing interfaces. There is no supplied evidence of active exploitation.

Technical view

The trace_event_file object could be freed when its kprobe event was removed while tracefs still retained an open file reference. Closing or writing through that reference then accessed freed memory. The upstream correction adds reference counting and a FREED flag, delaying release and blocking changes after event removal.

Likely exposure

Exposure is limited to Linux systems running an affected kernel where a local user can access the relevant tracefs tracing and kprobe interfaces. The supplied version data marks several kernel releases as affected, but its version structure is ambiguous; confirm applicability through the operating-system vendor.

Exploitation context

The CVSS vector is local, low-complexity, low-privilege, requires no user interaction, and scores 7.8. The source demonstrates a reproducible kernel crash. It does not establish remote exploitation, privilege escalation, data compromise, public weaponization, or active exploitation. The supplied KEV indicator is false.

Researcher notes

The demonstrated sequence creates a kprobe event, retains its enable file, removes the event, then releases the stale reference. The flaw is described as a use-after-free causing a NULL-pointer kernel fault. Assess downstream backports by fix presence, not upstream version numbers alone. The supplied affected-version records require vendor interpretation.

Mitigation direction

  • Apply a vendor-supported kernel update that incorporates the referenced trace_event_file reference-counting correction.
  • Check distribution security guidance to map the CVE accurately to packaged kernel versions.
  • Until patched, restrict untrusted local access to tracing and kprobe event-management interfaces.
  • Prioritize exposed multi-user hosts and systems where a kernel crash would disrupt critical services.

Validation and detection

  • Record the running kernel and distribution package versions on potentially exposed Linux systems.
  • Compare package versions with current distribution advisories and the referenced upstream stable commits.
  • Verify whether tracefs and kprobe event-management interfaces are enabled and accessible to untrusted local users.
  • Confirm the updated kernel is running after remediation; installation alone may leave the previous kernel active.
Prepared
Confidence
high
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.

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CVE-2023-52879 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
2ADP providers
8Source 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-2023-52879Attack 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
CVECVE Program Container

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinuxe6807c873d8791ae5a5186ad05ec66cab926539a, 407bf1c140f0757706c0b28604bcc90837d45ce2, fa6d449e4d024d8c17f4288e0567d28ace69415c, a46bf337a20f9edd3c8041b025639842280d0575, 9beec04370132a7a6cd1aa9897f6fffc6262ff28, f5ca233e2e66dc1c249bf07eefa37e34a6c9346a, f5ca233e2e66dc1c249bf07eefa37e34a6c9346a, 5.4.258, 5.10.198, 5.15.134, 6.1.55, 6.5.5unaffected
LinuxLinux6.6, 0, 5.4.262, 5.10.202, 5.15.140, 6.1.64, 6.5.13, 6.6.1, 6.7affected
Weakness

CWE details

No CWE listed

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