PT-2021-8250 · Linux · Linux Kernel

Colin Ian King + 1 · Published 2021-06-24 · Updated 2025-04-02 · CVE-2021-47312

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 The issue is related to a null pointer dereference in the netfilter component of the Linux kernel, specifically in the nf tables module. This occurs when the chain->flags & NFT CHAIN HW OFFLOAD condition is false, leading to nft flow rule create not being called and the flow variable being NULL. As a result, the error handling path to err destroy flow rule will attempt to call nft flow rule destroy on a null flow, causing a null pointer dereference. The fix involves only calling nft flow rule destroy if the flow is non-null.

Recommendations 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:2025-00788

CVE-2021-47312

Affected Products

Linux Kernel

References · 13

• https://security-tracker.debian.org/tracker/CVE-2021-47312 · Vendor Advisory
• https://git.kernel.org/stable/c/4ca041f919f13783b0b03894783deee00dbca19a · Patch
• https://nvd.nist.gov/vuln/detail/CVE-2021-47312 · Security Note
• https://git.kernel.org/stable/c/70a5a1950cca02c5cd161bb3846b4d983eed97d3 · Patch
• https://wiki.astralinux.ru/astra-linux-se81-bulletin-20241206SE81 · Vendor Advisory
• https://osv.dev/vulnerability/CVE-2021-47312 · Vendor Advisory
• https://ubuntu.com/security/CVE-2021-47312 · Vendor Advisory
• https://osv.dev/vulnerability/UBUNTU-CVE-2021-47312 · Vendor Advisory
• https://bdu.fstec.ru/vul/2025-00788 · Security Note
• https://cve.org/CVERecord?id=CVE-2021-47312 · Security Note
• https://t.me/cvenotify/117353 · Telegram Post
• https://git.kernel.org/linus/4ca041f919f13783b0b03894783deee00dbca19a · Note
• https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=4ca041f919f13783b0b03894783deee00dbca19a · Note