VulnerabilityPublished 7 Nov 2026

CVE-2026-99281: Linux kernel · tun: Require CAP_NET_ADMIN to attach to an ownerless device

Source GCVE Database

Compare

Authoritative record:CVE-2026-99281· High

Not known to be exploited · fixed in ffdf678dd16610e3f006dac904bd37c09684673c : patch Linux kernel soon.

Data as of 7 Nov 2026, 16:04 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 ffdf678dd16610e3f006dac904bd37c09684673c, e53d1cf05da8ea58a5743b7ce5894fb51b0b9700, 2f92c0286cfd58bff9d6d54c01a771073d5eb775

Exploitation evidence

Disclosed: evidence found.
CVE published 7 Nov 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 7 Nov 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-cfrf-w8r8-rf8x

What to do

Upgrade Linux kernel to ffdf678dd16610e3f006dac904bd37c09684673c, e53d1cf05da8ea58a5743b7ce5894fb51b0b9700 or 2f92c0286cfd58bff9d6d54c01a771073d5eb775.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ ca6bb5d7ab22ac79f608fe6cbc6b12de6a5a19f0, < ffdf678dd16610e3f006dac904bd37c09684673c	Fixed in ffdf678dd16610e3f006dac904bd37c09684673c
LinuxLinux	Affected ≥ ca6bb5d7ab22ac79f608fe6cbc6b12de6a5a19f0, < e53d1cf05da8ea58a5743b7ce5894fb51b0b9700	Fixed in e53d1cf05da8ea58a5743b7ce5894fb51b0b9700
LinuxLinux	Affected ≥ ca6bb5d7ab22ac79f608fe6cbc6b12de6a5a19f0, < 2f92c0286cfd58bff9d6d54c01a771073d5eb775	Fixed in 2f92c0286cfd58bff9d6d54c01a771073d5eb775
LinuxLinux	Affected =2.6.18	Fixed in–

AI-suggested

A fix has been implemented in the Linux kernel to require CAP_NET_ADMIN capability when attaching to ownerless tun devices. Users should update to a kernel version that includes this fix. No additional mitigation is required as the patch addresses the vulnerability directly.

Description

A vulnerability in the Linux kernel's tun driver allowed attaching to ownerless tun devices without requiring CAP_NET_ADMIN capability. This issue has been fixed by enforcing CAP_NET_ADMIN for attaching to devices that have no assigned owner or group, closing a loophole that previously allowed unauthorized access. The fix preserves existing ownership checks and corrects the capability check placement.

References

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