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CVE Record

CVE-2026-23138: tracing: Add recursion protection in kernel stack trace recording

In the Linux kernel, the following vulnerability has been resolved: tracing: Add recursion protection in kernel stack trace recording A bug was reported about an infinite recursion caused by tracing the rcu events with the kernel stack trace trigger enabled. The stack trace code called back into RCU which then called the stack trace again. Expand the ftrace recursion protection to add a set of bits to protect events from recursion. Each bit represents the context that the event is in (normal, softirq, interrupt and NMI). Have the stack trace code use the interrupt context to protect against recursion. Note, the bug showed an issue in both the RCU code as well as the tracing stacktrace code. This only handles the tracing stack trace side of the bug. The RCU fix will be handled separately.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

This Linux kernel issue is an infinite recursion bug in tracing. When RCU events are traced with the kernel stack trace trigger enabled, stack trace recording can call back into RCU and repeat. The public record does not provide CVSS, confirmed exploitation, or a full impact statement.

Executive priority

Treat as a stability-risk kernel maintenance item until more severity data appears. Prioritize systems where kernel tracing is used for diagnostics or observability, then fold remediation into normal kernel patch cycles unless vendor guidance raises urgency.

Technical view

The fix expands ftrace recursion protection with per-context event bits for normal, softirq, interrupt, and NMI contexts. Stack trace recording uses interrupt-context protection to prevent recursive tracing. The record notes this addresses only the tracing stacktrace side; an RCU-side fix is separate.

Likely exposure

Exposure is limited to Linux systems running affected kernel versions or downstream builds containing the vulnerable tracing behavior. Practical exposure likely depends on whether kernel tracing, RCU events, and stack trace triggers are used. Distribution backports may change version-based conclusions.

Exploitation context

The source describes a reported bug, not an active exploit. CISA KEV status is false in the bundle. No cited source shows public weaponization, exploit code, or in-the-wild abuse.

Researcher notes

Evidence is narrow: the public text identifies recursion between tracing stacktrace code and RCU, and the patch adds context-aware event recursion protection. No CVSS, CWE, exploit status, or complete RCU-side remediation is provided in the bundle.

Mitigation direction

  • Apply Linux stable or distribution kernel updates containing the referenced tracing fix.
  • Check vendor advisories for exact fixed package versions and backports.
  • Avoid the described tracing combination until patched, where operationally feasible.
  • Track the separate RCU-side fix mentioned by the kernel record.

Validation and detection

  • Inventory Linux kernel versions across servers, appliances, and images.
  • Map distribution packages to the CVE and referenced stable commits.
  • Confirm patched kernels include the tracing recursion protection change or vendor equivalent.
  • Review whether RCU event tracing with stack trace triggers is used.
  • Monitor kernel logs for recursion or tracing-related instability during diagnostics.
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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CVE-2026-23138 mapping review

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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
0ADP providers
5Source links

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.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux5f5fa7ea89dc82d34ed458f4d7a8634e8e9eefce, 5f5fa7ea89dc82d34ed458f4d7a8634e8e9eefce, 5f5fa7ea89dc82d34ed458f4d7a8634e8e9eefce, 5f5fa7ea89dc82d34ed458f4d7a8634e8e9eefceunaffected
LinuxLinux5.8, 0, 6.6.130, 6.12.78, 6.18.6, 6.19affected
Weakness

CWE details

No CWE listed

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