CVE-2021-47243
Last modified
CVE-2021-47243 is a high-severity vulnerability rated 7.1/10 on the CVSS scale. In the Linux kernel, the following vulnerability has been resolved: sch_cake: Fix out of bounds when parsing TCP options and header The TCP option parser in cake qdisc (cake_get_tcpopt and cake_tcph_may_drop) could read one byte out of bounds. When the length is 1, the execution flow gets into the loop, reads one byte of the opcode, and if the opcode is neither TCPOPT_EOL nor TCPOPT_NOP, it reads one more byte, which exceeds the length of 1. This fix is inspired by commit 9609dad263f8 ("ipv4: tcp_input: fix stack out of bounds when parsing TCP options."). v2 changes: Added doff validation in cake_get_tcphdr to avoid parsing garbage as TCP header. EPSS estimates a 0.26% chance of exploitation in the next 30 days.
Description
In the Linux kernel, the following vulnerability has been resolved: sch_cake: Fix out of bounds when parsing TCP options and header The TCP option parser in cake qdisc (cake_get_tcpopt and cake_tcph_may_drop) could read one byte out of bounds. When the length is 1, the execution flow gets into the loop, reads one byte of the opcode, and if the opcode is neither TCPOPT_EOL nor TCPOPT_NOP, it reads one more byte, which exceeds the length of 1. This fix is inspired by commit 9609dad263f8 ("ipv4: tcp_input: fix stack out of bounds when parsing TCP options."). v2 changes: Added doff validation in cake_get_tcphdr to avoid parsing garbage as TCP header. Although it wasn't strictly an out-of-bounds access (memory was allocated), garbage values could be read where CAKE expected the TCP header if doff was smaller than 5.
Metrics
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
Weakness Enumeration
Affected Software
| Vendor | Product | Versions | Update |
|---|---|---|---|
| Linux | Linux Kernel | >= 4.19, < 4.19.196 | — |
| Linux | Linux Kernel | >= 4.20, < 5.4.128 | — |
| Linux | Linux Kernel | >= 5.5, < 5.10.46 | — |
| Linux | Linux Kernel | >= 5.11, < 5.12.13 | — |
| Linux | Linux Kernel | 5.13 | Rc1 |
References
Timeline
- Published
- Last Modified
- Status
- Modified
Frequently Asked Questions
What is CVE-2021-47243?
How severe is CVE-2021-47243?
How do I fix CVE-2021-47243?
How Strix Helps
- How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
- Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
- PR ReviewsPentest every pull request so vulnerable code is caught before it ships to production.
- AI Penetration TestingHow AI-driven penetration testing continuously covers your attack surface.
Related CVEs from 2021
- CVE-2021-47237In the Linux kernel, the following vulnerability has been re…5.5
- CVE-2021-47238In the Linux kernel, the following vulnerability has been re…5.5
- CVE-2021-47239In the Linux kernel, the following vulnerability has been re…7.8
- CVE-2021-47240In the Linux kernel, the following vulnerability has been re…7.1
- CVE-2021-47241In the Linux kernel, the following vulnerability has been re…7.5
- CVE-2021-47242In the Linux kernel, the following vulnerability has been re…7.5
- CVE-2021-47244In the Linux kernel, the following vulnerability has been re…8.2
- CVE-2021-47245In the Linux kernel, the following vulnerability has been re…7.1
- CVE-2021-47246In the Linux kernel, the following vulnerability has been re…5.5
- CVE-2021-47247In the Linux kernel, the following vulnerability has been re…7.8
- CVE-2021-47248In the Linux kernel, the following vulnerability has been re…4.7
- CVE-2021-47249In the Linux kernel, the following vulnerability has been re…5.5
Are you affected by CVE-2021-47243?
Run a free Strix scan to check your systems for this vulnerability.
Scan your code nowSource: NVD / NIST