CVE-2026-74668: Linux kernel · packet: use consistent hard_header_len in TX_RING send path
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.8 High : upgrade to 6.8.0-1036.39 soon.
Data as of 28 Oct 2026, 01:00 UTC
- Patch
- Available – fixed in 6.8.0-1036.39
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 22 Aug 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.
What to do
Upgrade the Ubuntu linux-nvidia-tegra package to 6.8.0-1036.39.
Patches and advisories
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-gkepkg:deb/ubuntu/linux-gke?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
Description
In the Linux kernel, the following vulnerability has been resolved: packet: use consistent hard_header_len in TX_RING send path tpacket_snd() reads dev->hard_header_len independently for skb allocation and header construction in tpacket_fill_skb(). Concurrent netdevice reconfiguration can therefore make the reserved headroom smaller than the amount later pushed, or make copylen - hard_header_len negative. Snapshot hard_header_len once before processing ring frames and use it for the frame limit, headroom allocation, copy length, and skb construction. Pass the snapshot to tpacket_fill_skb(). The separate SOCK_DGRAM consistency problem between hard_header_len and header_ops->create is not addressed here.
References
- ubuntu.com/security/CVE-2026-74668 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-74668 (opens in a new tab)
- git.kernel.org/stable/c/d48ea5c9c4c34dc0df621f0e39ed3a16b644621a (opens in a new tab)
- git.kernel.org/stable/c/2a73b2c37ee3060a880b53cd24783d93fc7be5f8 (opens in a new tab)
- git.kernel.org/stable/c/e79f59a8527a49078cfaf8fe8fb5fcefc20c76d2 (opens in a new tab)
- git.kernel.org/stable/c/016763e829cac37b3234eace86fd0a4c560de4a7 (opens in a new tab)
- git.kernel.org/stable/c/27e068d1b35dbec10a3cf268887c94407be4badc (opens in a new tab)
- git.kernel.org/stable/c/d85d2fd54e901637c81d847811e03c662aee13cd (opens in a new tab)
- git.kernel.org/stable/c/9c7e8ff48c377bef18c3d178748aea0575b69ede (opens in a new tab)
- git.kernel.org/stable/c/21b5953e7494c16a42e6cd8cf110e18d13ae4a6b (opens in a new tab)
- ubuntu.com/security/notices/USN-8886-1 (opens in a new tab)