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CVE-2026-74684
net: tap: set skb->dev before parsing virtio net header in tap_get_user_xdp()
Overview
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().

Details
INFO

Published Date :

Aug. 22, 2026, 4:16 p.m.

Last Modified :

Aug. 22, 2026, 4:16 p.m.

Remotely Exploit :

No

Source :

416baaa9-dc9f-4396-8d5f-8c081fb06d67
Impact
Affected Products

The following products are affected by CVE-2026-74684 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

No affected product recoded yet

: Total Affected Vendor : 0 | Products : 0
Solution
Assign skb->dev before parsing virtio net header to prevent NULL pointer dereference.
  • Assign skb->dev before calling tun_vnet_hdr_to_skb().
  • Look up the tap device and assign skb->dev.
  • Preserve RCU read-side critical section across dev_queue_xmit().
References
References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2026-74684.

URL Resource
https://git.kernel.org/stable/c/164c31ee252ebd1ac8f44c2dfc5486b6d9a0379b
https://git.kernel.org/stable/c/3874892dd27d5387aa9a06f58d9060f18f351d24
https://git.kernel.org/stable/c/8b444b126cd8e4473e652f529753ed4dd1360a9c
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-74684 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-74684 weaknesses.

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2026-74684 vulnerability anywhere in the article.

Results are limited to the first 20 news articles due to potential performance issues.

The following table lists the changes that have been made to the CVE-2026-74684 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67

    Aug. 22, 2026

    Action Type Old Value New Value
    Added Affected [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '924a9bc362a5223cd448ca08c3dde21235adc310', 'lessThan': '8b444b126cd8e4473e652f529753ed4dd1360a9c', 'versionType': 'git'}, {'status': 'affected', 'version': '924a9bc362a5223cd448ca08c3dde21235adc310', 'lessThan': '164c31ee252ebd1ac8f44c2dfc5486b6d9a0379b', 'versionType': 'git'}, {'status': 'affected', 'version': '924a9bc362a5223cd448ca08c3dde21235adc310', 'lessThan': '3874892dd27d5387aa9a06f58d9060f18f351d24', 'versionType': 'git'}, {'status': 'affected', 'version': 'ea3fb2ce5fa794d02135f5c079e05cd6fc3f545d', 'versionType': 'git'}, {'status': 'affected', 'version': '54ef8243c3c8e90f1ea5792e6752e021a25c8eb3', 'versionType': 'git'}, {'status': 'affected', 'version': 'ca278267d6cd9544645731732455b6b20cb0e895', 'versionType': 'git'}, {'status': 'affected', 'version': 'faa3baa2828c5e1c4374f3e60041f75c64f5fcb6', 'versionType': 'git'}, {'status': 'affected', 'version': '99b1d3f74b9ef72c2f74c8e4c078e1bc0706e748', 'versionType': 'git'}, {'status': 'affected', 'version': '4.14.226', 'lessThan': '4.15', 'versionType': 'semver'}, {'status': 'affected', 'version': '4.19.181', 'lessThan': '4.20', 'versionType': 'semver'}, {'status': 'affected', 'version': '5.4.106', 'lessThan': '5.5', 'versionType': 'semver'}, {'status': 'affected', 'version': '5.10.24', 'lessThan': '5.11', 'versionType': 'semver'}, {'status': 'affected', 'version': '5.11.7', 'lessThan': '5.12', 'versionType': 'semver'}], 'programFiles': ['drivers/net/tap.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '5.12'}, {'status': 'unaffected', 'version': '0', 'lessThan': '5.12', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '6.18.45', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.1.9', 'versionType': 'semver', 'lessThanOrEqual': '7.1.*'}, {'status': 'unaffected', 'version': '7.2', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['drivers/net/tap.c'], 'defaultStatus': 'affected'}]
    Added 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().
    Added Reference https://git.kernel.org/stable/c/164c31ee252ebd1ac8f44c2dfc5486b6d9a0379b
    Added Reference https://git.kernel.org/stable/c/3874892dd27d5387aa9a06f58d9060f18f351d24
    Added Reference https://git.kernel.org/stable/c/8b444b126cd8e4473e652f529753ed4dd1360a9c
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
CVSS
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