VulnerabilityPublished 28 Oct 2026

CVE-2026-99167: Linux kernel · net/sched: fix use-after-free in __tcf_action_put()

Source GCVE Database

Authoritative record:CVE-2026-99167

Not known to be exploited · fixed in 2465d27ef90de9105c2bffb6c35f8ce08918e642 : patch Linux kernel soon.

Data as of 28 Oct 2026, 13:57 UTC

Severity

High

Rated High by Threat Radar's AI analysis · CVSS not yet scored by NVD

Patch: Available – fixed in 2465d27ef90de9105c2bffb6c35f8ce08918e642, 7b16eb911091aae237a8673da94e4dfb9cd21d54, 2e012e431aa271ef3c84206f48854f539c03bff0

Exploitation evidence

Disclosed: evidence found.
CVE published 28 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

ghsa-5mc4-5p5h-x8vj

What to do

Upgrade Linux kernel to 2465d27ef90de9105c2bffb6c35f8ce08918e642, 7b16eb911091aae237a8673da94e4dfb9cd21d54 or 2e012e431aa271ef3c84206f48854f539c03bff0.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ 16af6067392c40e454e49eec834843ab03643d96, < 2465d27ef90de9105c2bffb6c35f8ce08918e642	Fixed in 2465d27ef90de9105c2bffb6c35f8ce08918e642
LinuxLinux	Affected ≥ 16af6067392c40e454e49eec834843ab03643d96, < 7b16eb911091aae237a8673da94e4dfb9cd21d54	Fixed in 7b16eb911091aae237a8673da94e4dfb9cd21d54
LinuxLinux	Affected ≥ 16af6067392c40e454e49eec834843ab03643d96, < 2e012e431aa271ef3c84206f48854f539c03bff0	Fixed in 2e012e431aa271ef3c84206f48854f539c03bff0
LinuxLinux	Affected =4.19	Fixed in–

AI-suggested

A fix is available that holds the action IDR mutex during the critical operations to prevent use-after-free. Users should apply the official Linux kernel patch that addresses this issue. Since this is a kernel vulnerability, updating to a patched kernel version is the recommended remediation.

Description

A use-after-free vulnerability in the Linux kernel's net/sched subsystem was fixed in the __tcf_action_put() function. The flaw involved decrementing the reference count before the binding count, allowing another thread to free the action and causing subsequent access to freed memory. This was detected by KASAN as a slab-use-after-free error. The fix involves holding the action IDR mutex across both counter updates and IDR removal to prevent premature freeing.

References

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