VulnerabilityPublished 17 Sep 2026Updated 30 Oct 2026

CVE-2026-93100: Linux kernel · fs/resctrl: Prevent use-after-free in rdtgroup_kn_put()

Source GCVE Database

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Authoritative record:CVE-2026-93100· High

Not known to be exploited · fixed in f5bcf539484d2d604c2f2330e09487ea090b21c7 : patch Linux kernel soon.

Data as of 30 Oct 2026, 18:18 UTC

Severity

High

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

Thin evidence

One scorer or none

Patch: Available – fixed in f5bcf539484d2d604c2f2330e09487ea090b21c7, ae69f936e8ffed553d899ba4c02f8a7461a89e54, 971b40e3ca1279ca4917889e0195d33b66d071a4 +7

Exploitation evidence

Disclosed: evidence found.
CVE published 17 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: 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 30 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.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), 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-x642-fqm9-qj5q

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected >=4.14.170 <4.15 >=4.19.102 <4.20 >=5.4.18 <5.5 >=5.5.2 <5.6	Fixed in f5bcf539484d2d604c2f2330e09487ea090b21c7 ae69f936e8ffed553d899ba4c02f8a7461a89e54 971b40e3ca1279ca4917889e0195d33b66d071a4 906b3044dbf7c38cc411f7cf457c811363161e3b 828ff461c136b95d13b8d712c0a7a06a640e313a 5.6 5.5 4c593c62c1499665baebbb41b70e2c9b7e947b86 4.20 4.15
LinuxLinux	Affected =5.6	Fixed in–

AI-suggested

A fix has been implemented in the Linux kernel that replaces the atomic decrement operation with one that acquires the rdtgroup_mutex, preventing the race condition. Users should apply the official kernel update containing this patch to remediate the vulnerability. No additional mitigations are indicated.

Description

A use-after-free vulnerability was identified and resolved in the Linux kernel's resctrl filesystem component, specifically in the rdtgroup_kn_put() function. The flaw arises from a race condition between two paths that free rdtgroup structures, potentially leading to double free or use-after-free scenarios. The fix involves synchronizing reference count decrement and flag inspection under a mutex to prevent concurrent access issues.

References

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