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VulnerabilityPublished Updated

CVE-2026-74684: Linux kernel · net: tap: set skb->dev before parsing virtio net header in tap_get_user_xdp()

Affects Linux kernelSource CVE Database V5

0

Not known to be exploited · CVSS 7.1 High · fixed in 3874892dd27d5387aa9a06f58d9060f18f351d24 : patch Linux kernel soon.

Data as of 26 Oct 2026, 15:59 UTC

CVSS 3.1 base score
7.1High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.1% chance of exploitation in 30 days – higher than 3% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CISA SSVC
Exploitation
No evidence of active exploitation and no public proof of concept
Automatable
Attackers cannot reliably automate steps 1–4 of the kill chain
Technical impact
Limited control over the software or limited information exposure

CISA SSVC assessment, 2026-10-16.

Patch
Available – fixed in 3874892dd27d5387aa9a06f58d9060f18f351d24, 15583b07fd691a844fbf7b3ad612cdc9e9a657c0, 164c31ee252ebd1ac8f44c2dfc5486b6d9a0379b +7
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 22 Aug 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq 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 to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
LinuxLinuxAffected
  • >=4.14.226 <4.15
  • >=4.19.181 <4.20
  • >=5.4.106 <5.5
  • >=5.10.24 <5.11
  • >=5.11.7 <5.12
Fixed in
  • 3874892dd27d5387aa9a06f58d9060f18f351d24
  • 15583b07fd691a844fbf7b3ad612cdc9e9a657c0
  • 164c31ee252ebd1ac8f44c2dfc5486b6d9a0379b
  • 61dd022c55c7307ec119e5672cb141cccbecf3b1
  • 8b444b126cd8e4473e652f529753ed4dd1360a9c
  • 5.12
  • 5.11
  • 5.5
  • 4.20
  • 4.15
LinuxLinuxAffected
  • =5.12
Fixed in–

Description

In the Linux kernel, the following vulnerability has been resolved: net: tap: set skb->dev before parsing virtio net header in tap_get_user_xdp() The commit 4f61f133f354 ("net: tap: NULL pointer derefence in dev_parse_header_protocol when skb->dev is null") fixed a crash in tap_get_user() by assigning skb->dev before calling tun_vnet_hdr_to_skb(). This is required because virtio_net_hdr_to_skb() may invoke dev_parse_header_protocol(), which dereferences skb->dev. Without the assignment, a NULL pointer dereference can occur. However, tap_get_user_xdp() still parses the virtio-net header before assigning skb->dev. When the vhost TX path passes an XDP buffer containing a GSO virtio-net header but the protocol is set to zero on purpose, tun_vnet_hdr_to_skb() can reach dev_parse_header_protocol() while skb->dev is still NULL, resulting in a crash. Fix this by looking up the tap device and assigning skb->dev before calling tun_vnet_hdr_to_skb(), matching the ordering already used in tap_get_user(). Preserve the existing RCU read-side critical section across dev_queue_xmit().

References

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