PT-2025-7960 · Linux+5 · Linux Kernel+5

Syzbot · Published 2022-01-18 · Updated 2025-10-14 · CVE-2021-47649

Positive Technologies (AI Summary)

CVSS v3.1

5.5

Medium

Base vector

AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Name of the Vulnerable Software and Affected Versions Linux kernel (affected versions not specified)

Description A issue in the Linux kernel has been identified where the udmabuf validation of ubuf->pagecount is insufficient. This occurs when a user creates a udmabuf with list.size == 0, resulting in ubuf->pagecount being zero. This causes kmalloc array() to return ZERO PTR, leading to a general protection fault (GPF) in sg alloc append table from pages().

Recommendations For the affected Linux kernel version, validate ubuf->pagecount before passing it to kmalloc array() to prevent the GPF in sg alloc append table from pages(). At the moment, there is no information about a newer version that contains a fix for this vulnerability.

NULL Pointer Dereference

Weakness Enumeration

CWE-476

Related Identifiers

BDU:2026-04074

CESA-2022_7683

CVE-2021-47649

RHSA-2022:7683

RHSA-2022:8267

RHSA-2022_7683

RHSA-2022_8267

SUSE-SU-2025:1027-1

SUSE-SU-2025:1176-1

SUSE-SU-2025:1183-1

SUSE-SU-2025:1241-1

SUSE-SU-2025_1027-1

SUSE-SU-2025_1241-1

Affected Products

Astra Linux

Centos

Linux Kernel

Red Hat

Red Os

Suse

References · 1339

• https://git.kernel.org/stable/c/a3728d32fc61eb0fe283cb8ff60b2c8f751e2202 · Patch
• https://git.kernel.org/stable/c/811b667cefbea9cb7511a874b169d6a92907137e · Patch
• https://git.kernel.org/stable/c/9e9b4a269f84d3230f2af84ff42322db676440d9 · Patch
• https://osv.dev/vulnerability/SUSE-SU-2025:1183-1 · Vendor Advisory
• https://osv.dev/vulnerability/CVE-2021-47649 · Vendor Advisory
• https://osv.dev/vulnerability/SUSE-SU-2025:1176-1 · Vendor Advisory
• https://ubuntu.com/security/CVE-2021-47649 · Vendor Advisory
• https://git.kernel.org/stable/c/5d50f851dd307c07ca5591297093f19967c834a9 · Patch
• https://security-tracker.debian.org/tracker/CVE-2021-47649 · Vendor Advisory
• https://git.kernel.org/stable/c/2b6dd600dd72573c23ea180b5b0b2f1813405882 · Patch
• https://nvd.nist.gov/vuln/detail/CVE-2021-47649 · Security Note
• https://osv.dev/vulnerability/SUSE-SU-2025:1241-1 · Vendor Advisory
• https://git.kernel.org/stable/c/b267a8118c2b171bf7d67b90ed64154eeab9fae0 · Patch
• https://osv.dev/vulnerability/SUSE-SU-2025:1027-1 · Vendor Advisory
• https://bdu.fstec.ru/vul/2026-04074 · Security Note