PT-2024-11250 · Linux+1 · Linux Kernel+1

Maxim Mikityanskiy · Published 2021-06-10 · Updated 2024-12-30 · CVE-2021-47243

Positive Technologies (AI Summary)

CVSS v3.1

7.1

High

Base vector

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

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

Description The TCP option parser in the Linux kernel's cake qdisc could read one byte out of bounds when parsing TCP options and headers. This occurs when the length is 1, and the execution flow reads one byte of the opcode. If the opcode is neither TCPOPT EOL nor TCPOPT NOP, it reads one more byte, exceeding the length of 1. The fix adds doff validation in cake get tcphdr to avoid parsing garbage as a TCP header. Garbage values could be read where CAKE expected the TCP header if doff was smaller than 5.

Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.

Out of bounds Read

Weakness Enumeration

CWE-125

Related Identifiers

BDU:2025-07334

CVE-2021-47243

Affected Products

Astra Linux

Linux Kernel

References · 22

• https://git.kernel.org/stable/c/3b491dd593d582ceeb27aa617600712a6bd14246 · Patch
• https://git.kernel.org/stable/c/ba91c49dedbde758ba0b72f57ac90b06ddf8e548 · Patch
• https://bdu.fstec.ru/vul/2025-07334 · Security Note
• https://git.kernel.org/stable/c/3371392c60e2685af30bd4547badd880f5df2b3f · Patch
• https://git.kernel.org/stable/c/4cefa061fc63f4d2dff5ab4083f43857cd7a2335 · Patch
• https://git.kernel.org/stable/c/595897ef118d6fe66690c4fc5b572028c9da95b7 · Patch
• https://osv.dev/vulnerability/CVE-2021-47243 · Vendor Advisory
• https://cve.org/CVERecord?id=CVE-2021-47243 · Security Note
• https://nvd.nist.gov/vuln/detail/CVE-2021-47243 · Security Note
• https://osv.dev/vulnerability/DEBIAN-CVE-2021-47243 · Vendor Advisory
• https://security-tracker.debian.org/tracker/CVE-2021-47243 · Vendor Advisory
• https://ubuntu.com/security/CVE-2021-47243 · Vendor Advisory
• https://osv.dev/vulnerability/UBUNTU-CVE-2021-47243 · Vendor Advisory
• https://twitter.com/CVEnew/status/1792928073970573676 · Twitter Post
• https://git.linuxtesting.ru/pub/scm/linux/kernel/git/lvc/linux-stable.git/commit/?h=v5.10.176-lvc1&id=3b491dd593d582ceeb27aa617600712a6bd14246 · Note