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NVD / CVE Program· CNA Linux

CVE-2026-99235: tracing: Save the event file instead of the compatible histogram

Noroxi assessment

Priority: Monitor (action score 31/100)

  • 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: 0.12% (FIRST EPSS).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Linux Linux 173914501b97236d7ea7dc2af7f30feddd4e1436, 3609ada3c12cecfb0ae5ee82ef4f86c5f18a2dea, 7a111ba0d1b74c99bc8f096565dc71945f694254.

Low priority for now. Upgrade to Linux Linux 173914501b97236d7ea7dc2af7f30feddd4e1436, 3609ada3c12cecfb0ae5ee82ef4f86c5f18a2dea, 7a111ba0d1b74c99bc8f096565dc71945f694254 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: Save the event file instead of the compatible histogram create_field_var_hist() creates a histogram on the matched event to supply a field variable, and records it on the target so it can be torn down later: hist_data = find_compatible_hist(target_hist_data, file); ... /* Save the compatible histogram information */ var_hist->hist_data = hist_data; hist_data is not the histogram it creates. It is one that was already there, whose keys the new one copies. The saved pointer has a single user, unregister_field_var_hists(), which runs when the target is removed: file = hist_data->field_var_hists[i]->hist_data->event_file; find_compatible_hist() matches on keys alone, so it can pick one with no variables of its own. check_var_refs() then returns false and the user can remove it while the target still points at it: BUG: KASAN: slab-use-after-free in event_hist_trigger_free+0x2b2/0x320 Read of size 8 at addr ffff8880093b90e0 by task init/1 Freed by task 1: kfree+0x154/0x420 event_hist_trigger_free+0x1d5/0x320 event_hist_trigger_parse+0x35f3/0x69e0 trigger_process_regex+0x1a6/0x250 Save the event file instead. It is all the dereference ever wanted, and it does not go away when the user removes a trigger.

HighCVSS 7.8 · v3.1—No exploit Fix available
Published
Nov 2, 2026
Updated
Nov 3, 2026
EPSS
0.1% · 2th percentile
CWE
—

Report tools

JSON

Action score

31

Monitor

Low priority for now.

CVSS
31 / 40 · 7.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

CNA vs NVD score

NVD
—
CNA · Linux
7.8
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

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  • No public exploit code on record
  • A fix has been released

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When you'll hear from us

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  • when exploit code appears or is weaponized
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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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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 a6165126b1a1b26342b55be6eb6ee23af8756abaaffected · git
    • 02205a6752f223779a1b0e9e8ffacbea6e717851 and later · before 173914501b97236d7ea7dc2af7f30feddd4e1436affected · git
    • 02205a6752f223779a1b0e9e8ffacbea6e717851 and later · before ac815a379644b2ad5008a009a3516ada31b5dd82affected · git
    • 02205a6752f223779a1b0e9e8ffacbea6e717851 and later · before 8b307d64a60548e4a74cb746f74d7ed4bd49965eaffected · git
    • 02205a6752f223779a1b0e9e8ffacbea6e717851 and later · before 7a111ba0d1b74c99bc8f096565dc71945f694254affected · git
    • 02205a6752f223779a1b0e9e8ffacbea6e717851 and later · before 3609ada3c12cecfb0ae5ee82ef4f86c5f18a2deaaffected · git
    • 02205a6752f223779a1b0e9e8ffacbea6e717851 and later · before 9631dbccd3c649b567a5aafffea6b00634183997affected · git
    • 02205a6752f223779a1b0e9e8ffacbea6e717851 and later · before 7cafc82e6153f05a221be678cd649d02e06ba909affected · git
    • 02205a6752f223779a1b0e9e8ffacbea6e717851 and later · before d5c42664fc094899af9aae5300b27fe8fdb658efaffected · 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-2026-99233Nov 2, 2026 · tracing/histograms: Verify event_call identity when updating synth_event refcount
    31Monitor
  • ← EarlierCVE-2026-99234Nov 2, 2026 · tracing: Unregister field variable histograms when the command fails
    0Monitor
  • Later →CVE-2026-99236Nov 2, 2026 · tracing: Reject incomplete event filter expressions
    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 Linux173914501b97236d7ea7dc2af7f30feddd4e1436Vendor (CNA)
Linux Linux3609ada3c12cecfb0ae5ee82ef4f86c5f18a2deaVendor (CNA)
Linux Linux7a111ba0d1b74c99bc8f096565dc71945f694254Vendor (CNA)
Linux Linux7cafc82e6153f05a221be678cd649d02e06ba909Vendor (CNA)
Linux Linux8b307d64a60548e4a74cb746f74d7ed4bd49965eVendor (CNA)
Linux Linux9631dbccd3c649b567a5aafffea6b00634183997Vendor (CNA)
Linux Linuxa6165126b1a1b26342b55be6eb6ee23af8756abaVendor (CNA)
Linux Linuxac815a379644b2ad5008a009a3516ada31b5dd82Vendor (CNA)
Linux Linuxd5c42664fc094899af9aae5300b27fe8fdb658efVendor (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

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

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

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

—

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

nvd-secondary

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.

All records