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NVD / CVE Program· CNA Linux

CVE-2026-97935: tracing: Set the trace clock before registering the histogram trigger

Noroxi assessment

Priority: Monitor (action score 0/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.17% (FIRST EPSS).
  • Fixed version: Linux Linux 3568dabef3fb56517777ab981584f72ab1e90186, 578d39ab420b18b76a12fc8d0573ec041a84da28, 65d1e28198f344832a8a63e8ccf84b8f65b92a32; azl3 kernel 6.6.157.1-1 on Azure Linux 3.0 Release Notes.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 3568dabef3fb56517777ab981584f72ab1e90186, 578d39ab420b18b76a12fc8d0573ec041a84da28, 65d1e28198f344832a8a63e8ccf84b8f65b92a32; azl3 kernel 6.6.157.1-1 on Azure Linux 3.0 Release Notes or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

In the Linux kernel, the following vulnerability has been resolved: tracing: Set the trace clock before registering the histogram trigger hist_register_trigger() puts the trigger on the global named_triggers list in cmd_ops->init(), and only then sets the trace clock: if (data->cmd_ops->init) { ret = data->cmd_ops->init(data); if (ret < 0) goto out; } if (hist_data->enable_timestamps) { ret = tracing_set_clock(file->tr, hist_data->attrs->clock); if (ret) { hist_err(tr, HIST_ERR_SET_CLOCK_FAIL, errpos(clock)); goto out; } The clock string is not checked anywhere before that call, so a named trigger using common_timestamp with an unknown clock fails after it has already become findable. event_hist_trigger_parse() then frees it without taking it off the list, and the next lookup by name reads the freed object: ~# cd /sys/kernel/tracing/events/sched/sched_switch ~# echo 'hist:name=foo:keys=common_pid:ts=common_timestamp:clock=bogus' > trigger bash: echo: write error: Invalid argument ~# echo 'hist:name=foo:keys=common_pid' > trigger BUG: KASAN: slab-use-after-free in find_named_trigger+0xac/0xc0 Read of size 8 at addr ffff88800915d760 by task init/1 find_named_trigger+0xac/0xc0 hist_register_trigger+0xc1/0x900 event_hist_trigger_parse+0x3146/0x6af0 event_trigger_write+0xce/0x160 Freed by task 63: kfree+0x154/0x420 trigger_kthread_fn+0xfd/0x160 Set the clock before the trigger is registered, so that nothing which can fail runs after it is published, the way commit 6f86bdeab633 ("tracing: Fix bad hist from corrupting named_triggers list") moved the registration below the rest of the setup. tracing_set_filter_buffering() is reference counted, so the init failure path has to drop the reference that the clock block now takes first.

—No exploit Fix available
Published
Sep 25, 2026
Updated
Oct 30, 2026
EPSS
0.1% · 7th percentile
CWE
—

Report tools

JSON

Action score

0

Monitor

Low priority for now.

CVSS
0 / 40 · —
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

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Noroxi analysis

What does it mean in your environment?

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 4.17affected
    • a4072fe85ba3671720cab0788291af953db27318 and later · before 85e6df6e9cd489de8e238596a68b89eee0c03b88affected · git
    • a4072fe85ba3671720cab0788291af953db27318 and later · before 3568dabef3fb56517777ab981584f72ab1e90186affected · git
    • a4072fe85ba3671720cab0788291af953db27318 and later · before c7b77c22adcf314ec8aa4807f01914dcbc62ed54affected · git
    • a4072fe85ba3671720cab0788291af953db27318 and later · before 578d39ab420b18b76a12fc8d0573ec041a84da28affected · git
    • a4072fe85ba3671720cab0788291af953db27318 and later · before cc6c4cf565b0c187c61ffd2e67a4dfb2427675adaffected · git
    • a4072fe85ba3671720cab0788291af953db27318 and later · before cfad128171f8e2237a3c723d6478ef2cfb3b9127affected · git
    • a4072fe85ba3671720cab0788291af953db27318 and later · before 65d1e28198f344832a8a63e8ccf84b8f65b92a32affected · git
    • a4072fe85ba3671720cab0788291af953db27318 and later · before 6ede78d0563a2a3ae3e46f9c07cedb5d79645429affected · git
    • before 4.17not affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12linuxfrom 0—
Debian:12linux-6.12before 6.12.113-1~deb12u16.12.113-1~deb12u1
Debian:13linuxbefore 6.12.113-16.12.113-1
Debian:14linuxbefore 7.2.7-17.2.7-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-74705udp: fix potential use-after-free in tunnel segmentation
    40Plan
  • CVE-2026-74612veth: fix skb length accounting after XDP frag adjustment
    40Plan
  • CVE-2026-74475vxlan: use neigh_ha_snapshot() in route_shortcircuit()
    40Plan

Published before and after this one in the same product

  • ← EarlierCVE-2026-97933Sep 25, 2026 · tracing: Take trace_array reference when opening a tracer options file
    0Monitor
  • ← EarlierCVE-2026-97934Sep 25, 2026 · tracing: Fix memory corruption from a "STACKTRACE" histogram key
    0Monitor
  • Later →CVE-2026-97936Sep 25, 2026 · tracing: Fix memory corruption from the histogram stacktrace modifier
    0Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux3568dabef3fb56517777ab981584f72ab1e90186Vendor (CNA)
Linux Linux578d39ab420b18b76a12fc8d0573ec041a84da28Vendor (CNA)
Linux Linux65d1e28198f344832a8a63e8ccf84b8f65b92a32Vendor (CNA)
Linux Linux6ede78d0563a2a3ae3e46f9c07cedb5d79645429Vendor (CNA)
Linux Linux85e6df6e9cd489de8e238596a68b89eee0c03b88Vendor (CNA)
Linux Linuxc7b77c22adcf314ec8aa4807f01914dcbc62ed54Vendor (CNA)
Linux Linuxcc6c4cf565b0c187c61ffd2e67a4dfb2427675adVendor (CNA)
Linux Linuxcfad128171f8e2237a3c723d6478ef2cfb3b9127Vendor (CNA)
azl3 kernel 6.6.157.1-1 on Azure Linux 3.0Release NotesMicrosoft (MSRC)
debian:linux6.12.113-1 · Debian:13Package registry (OSV)
debian:linux7.2.7-1 · Debian:14Package registry (OSV)
debian:linux-6.126.12.113-1~deb12u1 · Debian:12Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

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No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

Technical details

No CVSS vector for this record, so attack conditions can't be derived.

Weakness class (CWE)

—

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

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References

Show all references (7 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

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