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Vulnerability details: VCID-597p-ugu9-s7du
Vulnerability ID VCID-597p-ugu9-s7du
Aliases CVE-2026-31437
Summary 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.
Status Published
Exploitability None
Weighted Severity None
Risk None
Affected and Fixed Packages Package Details
Weaknesses (1)
CWE-476 NULL Pointer Dereference
System Score Found at
cvssv3 5.5 https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2026-31437.json
epss 0.00017 https://api.first.org/data/v1/epss?cve=CVE-2026-31437
epss 0.00017 https://api.first.org/data/v1/epss?cve=CVE-2026-31437
epss 0.00022 https://api.first.org/data/v1/epss?cve=CVE-2026-31437
epss 0.00022 https://api.first.org/data/v1/epss?cve=CVE-2026-31437
cvssv3.1 5.5 https://ftp.suse.com/pub/projects/security/yaml/suse-cvss-scores.yaml
Reference id Reference type URL
https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2026-31437.json
https://api.first.org/data/v1/epss?cve=CVE-2026-31437
https://ftp.suse.com/pub/projects/security/yaml/suse-cvss-scores.yaml
2460683 https://bugzilla.redhat.com/show_bug.cgi?id=2460683
No exploits are available.
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Found at https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2026-31437.json
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Found at https://ftp.suse.com/pub/projects/security/yaml/suse-cvss-scores.yaml
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Exploit Prediction Scoring System (EPSS)
Percentile 0.04052
EPSS Score 0.00017
Published At April 24, 2026, 12:55 p.m.
Date Actor Action Source VulnerableCode Version
2026-04-23T05:40:54.752589+00:00 Debian Importer Import https://security-tracker.debian.org/tracker/data/json 38.4.0