CVE-2026-63970: Linux kernel · vsock/virtio: bind uarg before filling zerocopy skb
Source GCVE Database
Not known to be exploited · CVSS 7.8 High · fixed in b62e2b2b4a50953ca952f3cd3f77dd62dc50fd5d : patch Linux kernel soon.
Data as of 26 Oct 2026, 17:16 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 7% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in b62e2b2b4a50953ca952f3cd3f77dd62dc50fd5d, 72194f65050958e4c8e069adb6c5d89ef81ca197, 5d317573f1d48e76cce5fb6250452b6e4102e0fb +1
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 19 Jul 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 Linux kernel to b62e2b2b4a50953ca952f3cd3f77dd62dc50fd5d, 72194f65050958e4c8e069adb6c5d89ef81ca197, 5d317573f1d48e76cce5fb6250452b6e4102e0fb or 1e584c304cfb94a759417130b1fc6d30b30c4cce.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in– |
AI-suggested
A fix has been implemented in the Linux kernel to address this vulnerability by changing the order of uarg binding and skb filling. Users should apply the official Linux kernel updates that include this patch. Since this is not a cloud service, remediation requires updating affected Linux kernel versions once the patch is released.
Description
In the Linux kernel, the following vulnerability has been resolved: vsock/virtio: bind uarg before filling zerocopy skb virtio_transport_send_pkt_info() allocates or reuses the zerocopy uarg before entering the send loop, but virtio_transport_alloc_skb() still fills the skb before it inherits that uarg. When fixed-buffer vectored zerocopy hits MAX_SKB_FRAGS, io_sg_from_iter() may partially attach managed frags and return -EMSGSIZE. The rollback path call kfree_skb() to free an skb that carries SKBFL_MANAGED_FRAG_REFS but no uarg, so skb_release_data() falls through to ordinary frag unref. Pass the uarg into virtio_transport_alloc_skb() and bind it immediately before virtio_transport_fill_skb(). This keeps control or no-payload skbs untouched while ensuring success and rollback share one lifetime rule.
References
- nvd.nist.gov/vuln/detail/CVE-2026-63970 (opens in a new tab)
- git.kernel.org/stable/c/1e584c304cfb94a759417130b1fc6d30b30c4cce (opens in a new tab)
- git.kernel.org/stable/c/5d317573f1d48e76cce5fb6250452b6e4102e0fb (opens in a new tab)
- git.kernel.org/stable/c/b62e2b2b4a50953ca952f3cd3f77dd62dc50fd5d (opens in a new tab)
- git.kernel.org/stable/c/72194f65050958e4c8e069adb6c5d89ef81ca197 (opens in a new tab)