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CVE.org (no NVD analysis yet)· CNA Linux

CVE-2026-99163: tracing/histograms: Reject non-stacktrace fields for synthetic stacktrace fields

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: 0.13% (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 1f36e4ddd05d540f363dbaa4c23042549f15b3ef, 326c45c9e201e3ff4c9e9e0e14c2c91364d6c8be, 5.10.273; azl3 kernel 6.6.157.1-1 on Azure Linux 3.0 Release Notes; azl3 kernel 6.6.159.1-1 on Azure Linux 3.0 6.6.161.1-1.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 1f36e4ddd05d540f363dbaa4c23042549f15b3ef, 326c45c9e201e3ff4c9e9e0e14c2c91364d6c8be, 5.10.273; azl3 kernel 6.6.157.1-1 on Azure Linux 3.0 Release Notes; azl3 kernel 6.6.159.1-1 on Azure Linux 3.0 6.6.161.1-1 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/histograms: Reject non-stacktrace fields for synthetic stacktrace fields In check_synth_field(), when a synthetic event field is a stacktrace (field->is_stack) and the histogram field is not a "long[" stacktrace array, validation falls through to the generic size and signedness comparison. Because parse_synth_field() sets a stacktrace field's type to "__data_loc unsigned long[]", its size is sizeof(u64) and synth_field_signed() marks it as signed. Consequently, any 8-byte signed scalar histogram field passes the fallback check, and its scalar value is subsequently dereferenced as a kernel stacktrace pointer in get_field_size() and trace_stack(). Furthermore, checking strstr(hist_field->type, "long[") is insufficient because tracepoint fields defined with __bitmask() or __rel_bitmask() also have type "__data_loc unsigned long[]" or "__rel_loc unsigned long[]", whilst create_hist_field() treats them as 4-byte scalar values without HIST_FIELD_FL_STACKTRACE. Propagate HIST_FIELD_FL_STACKTRACE to variable references and field variables (whilst excluding variable aliases from per-element stacktrace capture), and reject any mismatch between HIST_FIELD_FL_STACKTRACE and field->is_stack in check_synth_field().

HighCVSS 7.8 · v3.1—No exploit Fix available
Published
Oct 28, 2026
Updated
Oct 31, 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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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

    • 6.3affected
    • b9453380c1c542fd095a4dbe9251eeba4022bbce and later · before eba0a6365a0f38f7598a02fc7f9ee341c7efe7f5affected · git
    • 5f52389bdd9eafb63b3a2f804e02aeb17b6a5f55 and later · before 326c45c9e201e3ff4c9e9e0e14c2c91364d6c8beaffected · git
    • f3baa42afeea0d5f04ad31525e861199d02210cc and later · before 6c4e4946febb585d2fc93a02a0cd12cec715bb32affected · git
    • 00cf3d672a9dd409418647e9f98784c339c3ff63 and later · before 7e0d05a6234a984ac23b8a563fb7f66f2572b668affected · git
    • 00cf3d672a9dd409418647e9f98784c339c3ff63 and later · before 648687f2b448d8527cd7b112fe5d4bd0fec85a87affected · git
    • 00cf3d672a9dd409418647e9f98784c339c3ff63 and later · before 1f36e4ddd05d540f363dbaa4c23042549f15b3efaffected · git
    • 00cf3d672a9dd409418647e9f98784c339c3ff63 and later · before deb336ae7c7b341591a6862cf6fcfeca97c77dfdaffected · git
    • 00cf3d672a9dd409418647e9f98784c339c3ff63 and later · before a244c241593b5b38a08f0df2cb43c26574efbdcbaffected · git
    • 5.10.237 and later · before 5.10.273affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxfrom 0—
Debian:13linuxbefore 6.12.115-26.12.115-2
Debian:14linuxbefore 7.2.13-17.2.13-1

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-2026-99161Oct 28, 2026 · i2c: viai2c-wmt: Fix clock leak in wmt_i2c_probe()
    0Monitor
  • ← EarlierCVE-2026-99162Oct 28, 2026 · gpio: shared: fix use-after-free bug when adding shared proxies
    0Monitor
  • Later →CVE-2026-99164Oct 28, 2026 · spi: imx: fix slab corruption from undersized DMA bounce buffers
    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 Linux1f36e4ddd05d540f363dbaa4c23042549f15b3efVendor (CNA)
Linux Linux326c45c9e201e3ff4c9e9e0e14c2c91364d6c8beVendor (CNA)
Linux Linux5.10.273Vendor (CNA)
Linux Linux5.15.224Vendor (CNA)
Linux Linux6.1.191Vendor (CNA)
Linux Linux648687f2b448d8527cd7b112fe5d4bd0fec85a87Vendor (CNA)
Linux Linux6c4e4946febb585d2fc93a02a0cd12cec715bb32Vendor (CNA)
Linux Linux7e0d05a6234a984ac23b8a563fb7f66f2572b668Vendor (CNA)
Linux Linuxa244c241593b5b38a08f0df2cb43c26574efbdcbVendor (CNA)
Linux Linuxdeb336ae7c7b341591a6862cf6fcfeca97c77dfdVendor (CNA)
Linux Linuxeba0a6365a0f38f7598a02fc7f9ee341c7efe7f5Vendor (CNA)
azl3 kernel 6.6.157.1-1 on Azure Linux 3.0Release NotesMicrosoft (MSRC)
azl3 kernel 6.6.159.1-1 on Azure Linux 3.06.6.161.1-1 · Release NotesMicrosoft (MSRC)
debian:linux6.12.115-2 · 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 10, 2026+13 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).

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

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. CVSS— → 7.8
  2. Severity— → high
  3. Exploit maturity— → none
  4. Fix✗ → ✓

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

References

Show all references (7 more)

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

All records