CVE-2026-31437
5.5 · MEDIUMOverview
CVE-2026-31437 is a medium-severity vulnerability affecting linux linux_kernel. It was published on April 22, 2026 and has a CVSS 3.1 base score of 5.5 (MEDIUM).
This vulnerability has a CVSS 3.1 base score of 5.5, rated MEDIUM. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.
Technical Description
In the Linux kernel, the following vulnerability has been resolved:
netfs: Fix NULL pointer dereference in netfs_unbuffered_write() on retry
When a write subrequest is marked NETFS_SREQ_NEED_RETRY, the retry path
in netfs_unbuffered_write() unconditionally calls stream->prepare_write()
without checking if it is NULL.
Filesystems such as 9P do not set the prepare_write operation, so
stream->prepare_write remains NULL. When get_user_pages() fails with
-EFAULT and the subrequest is flagged for retry, this results in a NULL
pointer dereference at fs/netfs/direct_write.c:189.
Fix this by mirroring the pattern already used in write_retry.c: if
stream->prepare_write is NULL, skip renegotiation and directly reissue
the subrequest via netfs_reissue_write(), which handles iterator reset,
IN_PROGRESS flag, stats update and reissue internally.
Remediation
Check the references section for vendor advisories and patches from linux. Update linux_kernel to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected Products
| Vendor | Product | Versions | Status |
|---|---|---|---|
| linux | linux_kernel | >= 6.18.17, < 6.18.21 | Affected |
Frequently Asked Questions
What is CVE-2026-31437?
CVE-2026-31437 is a medium-severity vulnerability affecting linux linux_kernel. It was published on April 22, 2026 and has a CVSS 3.1 base score of 5.5 (MEDIUM).
How severe is CVE-2026-31437?
This vulnerability has a CVSS 3.1 base score of 5.5, rated MEDIUM. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.
How do I fix or remediate CVE-2026-31437?
Check the references section for vendor advisories and patches from linux. Update linux_kernel to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2026-31437?
CyberStrike's AI-powered security agents can automatically detect CVE-2026-31437 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
How CyberStrike Helps
AI agents map your attack surface to find vulnerabilities like this one.
Automated penetration testing that runs continuously, not just quarterly.
AI-driven PR review catches vulnerable dependencies before they ship.
Browser-based exploitation validates findings with real proof-of-concept.
Related MEDIUM CVEs from 2026
View all →Discourse is an open source discussion platform. In versions prior to 3.5.4, 2025.11.2, 2025.12.1, a
In libexpat before 2.7.4, the doContent function does not properly determine the buffer size bufSize
Buffer overflow vulnerability in the HDC module. Impact: Successful exploitation of this vulnerabili
ImageMagick is free and open-source software used for editing and manipulating digital images. Prior
A improper certificate validation vulnerability in Fortinet FortiAnalyzer 7.6.0 through 7.6.4, Forti
OpenClaw versions prior to 2026.3.1 fail to properly handle authentication bootstrap errors during s
File Browser is a file managing interface for uploading, deleting, previewing, renaming, and editing
Vulnerability of improper permission control in the theme setting module. Impact: Successful exploit
Access of resource using incompatible type ('type confusion') vulnerability in Samsung Open Source E
A flaw was found in Keycloak, specifically in the organization selection login page. A remote attack
Serendipity is a PHP-powered weblog engine. In versions 2.6-beta2 and below, the serendipity_setCoo
In iTerm2 through 3.6.9, displaying a .txt file can cause code execution via DCS 2000p and OSC 135 d