CVE-2026-99281: Linux kernel · tun: Require CAP_NET_ADMIN to attach to an ownerless device
Affects Linux kernelSource GCVE Database
Not known to be exploited.
Data as of 10 Nov 2026, 07:11 UTC
Rated by Threat Radar · CVSS not yet scored by NVD
Thin evidence
One scorer or noneExploitation 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 9 Nov 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.10linuxpkg:deb/ubuntu/linux?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.10linux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.10linux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.10linux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.10linux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.10linux-oraclepkg:deb/ubuntu/linux-oracle?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
A fix is available that enforces CAP_NET_ADMIN capability requirement when attaching to tun devices without an assigned owner or group. Users should update to a Linux kernel version that includes this fix. No additional mitigation is required as this patch closes the identified loophole.
Description
This vulnerability in the Linux kernel's tun driver fixes a security loophole where attaching to an ownerless tun device did not require CAP_NET_ADMIN capability. Previously, devices without an assigned owner or group could be attached to by any user, potentially allowing unauthorized access. The fix enforces that attaching to such devices now requires CAP_NET_ADMIN, closing this access gap while preserving existing ownership and permission models.
References
- ubuntu.com/security/CVE-2026-99281 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-99281 (opens in a new tab)
- git.kernel.org/stable/c/2f92c0286cfd58bff9d6d54c01a771073d5eb775 (opens in a new tab)
- git.kernel.org/stable/c/ffdf678dd16610e3f006dac904bd37c09684673c (opens in a new tab)
- git.kernel.org/stable/c/e53d1cf05da8ea58a5743b7ce5894fb51b0b9700 (opens in a new tab)