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NVD / CVE Program· CNA Linux

CVE-2026-99234: tracing: Unregister field variable histograms when the command fails

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: 0.18% (FIRST EPSS).
  • Fixed version: Linux Linux 431959fc76456cbba539279fe8967aa9391e6f23, 5afb9317e2eeb1c7021a82995ce244fda5a4bd4f, 8482ec5b65f606d5bbcec518e0afc69ad65ca414.

Low priority for now. Upgrade to Linux Linux 431959fc76456cbba539279fe8967aa9391e6f23, 5afb9317e2eeb1c7021a82995ce244fda5a4bd4f, 8482ec5b65f606d5bbcec518e0afc69ad65ca414 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: Unregister field variable histograms when the command fails An action that names a field on another event needs that field as a variable, so create_field_var_hist() registers a second hist trigger on that event to provide it, and records it in target_hist_data->field_var_hists[]. If a later part of the same command fails, create_actions() returns an error and event_hist_trigger_parse() jumps to out_free. The write fails with -EINVAL and sched_switch gets no trigger, but: # echo 'hist:keys=pid:ts0=common_timestamp.usecs' >> \ events/sched/sched_waking/trigger # echo 'my_synth u64 lat; int a; int b' >> synthetic_events # echo 'hist:keys=next_pid:wakeup_lat=common_timestamp.usecs-$ts0:\ onmatch(sched.sched_waking).my_synth($wakeup_lat,prio,nosuchfld)'\ >> events/sched/sched_switch/trigger # cat events/sched/sched_waking/trigger hist:keys=pid:vals=hitcount:ts0=common_timestamp.usecs:sort=hitcount:size=2048:clock=global [active] hist:keys=pid:vals=hitcount:synthetic_prio=prio:sort=hitcount:size=2048 [active] The second histogram is the one created for 'prio'. It is still active and still counting. out_free reaches destroy_field_var_hists(), which frees the field_var_hists[] entries, but never unregister_field_var_hists(), which is what removes the triggers and runs only from event_hist_trigger_free(). The entry is freed and the trigger is left with nothing tracking it. Unregister the field variable histograms in out_free as well, and record each one as soon as its trigger is registered rather than after the lookup that follows it, so no exit can leave a registered trigger untracked. The entry then belongs to field_var_hists[] and is released by destroy_field_var_hists(), so freeing it on that exit would be a double free.

—No exploit Fix available
Published
Nov 2, 2026
Updated
Nov 3, 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
    • 02205a6752f223779a1b0e9e8ffacbea6e717851 and later · before f21351d1c4cdcc6a68f03636a407c2af1a5e1e10affected · git
    • 02205a6752f223779a1b0e9e8ffacbea6e717851 and later · before dba0f492703956801149cc70b39d2650a37995c3affected · git
    • 02205a6752f223779a1b0e9e8ffacbea6e717851 and later · before a3d7ffd2409700748a495b645948fef48199206eaffected · git
    • 02205a6752f223779a1b0e9e8ffacbea6e717851 and later · before aae0ccd7326eef78dcdefffef3d1253e6f0615caaffected · git
    • 02205a6752f223779a1b0e9e8ffacbea6e717851 and later · before 8482ec5b65f606d5bbcec518e0afc69ad65ca414affected · git
    • 02205a6752f223779a1b0e9e8ffacbea6e717851 and later · before 431959fc76456cbba539279fe8967aa9391e6f23affected · git
    • 02205a6752f223779a1b0e9e8ffacbea6e717851 and later · before 5afb9317e2eeb1c7021a82995ce244fda5a4bd4faffected · git
    • 02205a6752f223779a1b0e9e8ffacbea6e717851 and later · before d0090baf02dd08f6e909f36f0ad54a4e80f5e79baffected · git
    • 02205a6752f223779a1b0e9e8ffacbea6e717851 and later · before 91c14d6c13096091c56304120aaa26e479130b8baffected · git

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxfrom 0—
Debian:13linuxbefore 6.12.115-16.12.115-1
Debian:14linuxbefore 7.2.14-17.2.14-1

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-2026-99232Nov 2, 2026 · tracing/syscalls: Use copy_from_user for the faultable syscall buffer
    0Monitor
  • ← EarlierCVE-2026-99233Nov 2, 2026 · tracing/histograms: Verify event_call identity when updating synth_event refcount
    31Monitor
  • Later →CVE-2026-99235Nov 2, 2026 · tracing: Save the event file instead of the compatible histogram
    31Monitor

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 Linux431959fc76456cbba539279fe8967aa9391e6f23Vendor (CNA)
Linux Linux5afb9317e2eeb1c7021a82995ce244fda5a4bd4fVendor (CNA)
Linux Linux8482ec5b65f606d5bbcec518e0afc69ad65ca414Vendor (CNA)
Linux Linux91c14d6c13096091c56304120aaa26e479130b8bVendor (CNA)
Linux Linuxa3d7ffd2409700748a495b645948fef48199206eVendor (CNA)
Linux Linuxaae0ccd7326eef78dcdefffef3d1253e6f0615caVendor (CNA)
Linux Linuxd0090baf02dd08f6e909f36f0ad54a4e80f5e79bVendor (CNA)
Linux Linuxdba0f492703956801149cc70b39d2650a37995c3Vendor (CNA)
Linux Linuxf21351d1c4cdcc6a68f03636a407c2af1a5e1e10Vendor (CNA)
debian:linux6.12.115-1 · Debian:13Package 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.

  1. Published
  2. Fix recordedsame day
  3. TodayNov 9, 2026+7 d
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).

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✗ → ✓
  2. Exploit maturity— → none

For records you follow, these changes also arrive as notifications. →

References

Show all references (8 more)

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

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