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TI-2026-83898 Aliases CVE-2026-99233GHSA-hqr3-rh3c-f6xh

Histogram registration corrupts synth_event refcount in Linux kernel

Priority LOW 33Published · Updated

Key facts

Attack vector
Local
Privileges required
Low
User interaction
None
Attack complexity
Low
Impact type
—
Confidentiality · integrity · availability
High · High · High
Fix status
Partial Red Hat: 5 without a fix

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat.

Summary

The Linux kernel from 4.17 is affected until the fixed versions named in the solution. Histogram registration and removal in tracing match synthetic events by basename only, so a histogram on a non-synthetic event with the same name changes the synthetic event's reference count. A local user with low privileges can cause the synthetic event to be freed while a histogram action still uses it, with high impact to confidentiality, integrity and availability.

Written with Claude Haiku 5.5 from the sources below · 2026-11-06

Description from the CNA

In the Linux kernel, the following vulnerability has been resolved: tracing/histograms: Verify event_call identity when updating synth_event refcount In event_hist_trigger_parse() and hist_unreg_all(), the histogram registration and unregistration paths look up find_synth_event() using trace_event_name(file->event_call) and adjust se->ref if a match is found. Because find_synth_event() only compares the event basename, registering or removing a histogram on a non-synthetic trace event whose basename matches a synthetic event erroneously modifies the synthetic event's reference count. If a histogram is registered on the non-synthetic event before the synthetic event is created and removed afterwards, se->ref is decremented without a matching increment, allowing the synthetic event to be freed while an active histogram action still holds a pointer to it. Introduce find_synth_event_call() to verify that &se->call matches file->event_call before adjusting se->ref.

Why it matters now

EPSS 0.00121 1st percentileScored 2026-11-07
Fix Partial Linux (Linux): 6.1.191, 6.6.161, 6.12.115 +4Red Hat: 5 without a fix

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

VendorProductAffected versionsFixed inStatusSource
LinuxLinux4.17 and later6.1.191, 6.6.161, 6.12.115, 6.18.60, 7.2.14, 7.3.1, 7.4-rc1Patch availableCNA
  • Linux VendorLinux Affected 4.17 and later Fixed in 6.1.191, 6.6.161, 6.12.115, 6.18.60, 7.2.14, 7.3.1, 7.4-rc1 Patch available CNA

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*——Linux
  • cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions — — ·Linux

Remediation

Fixed versions are 6.1.191, 6.6.161, 6.12.115, 6.18.60, 7.2.14, 7.3.1 and 7.4-rc1. Red Hat rates this Important and lists Red Hat Enterprise Linux 8, 9 and 10 and Red Hat OpenShift Container Platform 4 and 5 as affected without a fix, with the plan none_available.

Written with Claude Haiku 5.5 from the sources below · 2026-11-06

  • Fix · CNA Linux (Linux) Fixed in 6.1.191, 6.6.161, 6.12.115, 6.18.60, 7.2.14, 7.3.1, 7.4-rc1

Vendor assessments

Red Hat

Red Hat rating: Important. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Enterprise Linux 10AffectedNo fix yet
Red Hat Enterprise Linux 8AffectedNo fix yet
Red Hat Enterprise Linux 9AffectedNo fix yet
Red Hat OpenShift Container Platform 4AffectedNo fix yet
Red Hat OpenShift Container Platform 5AffectedNo fix yet
Not affected: 2 products
  • Red Hat Enterprise Linux 6
  • Red Hat Enterprise Linux 7

Timeline

  1. 2026-11-02 Threatist record created from CVE-2026-99233
  2. 2026-11-02 Alias added: GHSA-hqr3-rh3c-f6xh
  3. 2026-11-03 Affected versions changed · Red Hat
  4. 2026-11-03 CVSS score added · Red Hat
  5. 2026-11-03 Fix available: Linux/Linux@3403d9bb27ebc3572bd048620746b4414e073bf9, Linux/[email protected] · CNA
  6. 2026-11-03 1 new reference · CNA
  7. 2026-11-04 Priority changed: MEDIUM → LOW

References

Other 7

  • TI-2025-26358 tls: fix handling of zero-length records on the rx_list KEVCVSS 3.1CRITICAL 9.8
  • TI-2026-38352 netfilter: bridge: make ebt_snat ARP rewrite writable KEVCVSS 3.1HIGH 8.8
  • TI-2021-02452 Incorrect authorization in Ubuntu linux kernel KEVCVSS 3.1HIGH 8.8
  • TI-2013-05264 The (1) get_user and (2) put_user API functions in the Linux kernel before 3.5.5 on the… KEVCVSS 3.1HIGH 8.8
  • TI-2022-00125 Integer overflow in kernel KEVCVSS 3.1HIGH 8.4
  • TI-2013-01864 The perf_swevent_init function in kernel/events/core.c in the Linux kernel before 3.8.9… KEVCVSS 3.1HIGH 8.4
See all 21741 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences