CVE-2021-47243
HighIn 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.
CVSS 3.1 score
7.1
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
Weakness type
CWE-125CVE-2021-47243 is a Out-of-bounds Read vulnerability
What is Out-of-bounds Read?
The product reads data past the end or before the beginning of the intended buffer. Learn more on MITRE CWE
References
The following references provide additional information about CVE-2021-47243 including vendor advisories, patch commits, exploit details, and third-party analysis. Links are sourced from the NIST NVD database.
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PatchKernel patch commithttps://git.kernel.org/stable/c/3371392c60e2685af30bd4547badd880f5df2b3f
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PatchKernel patch commithttps://git.kernel.org/stable/c/3b491dd593d582ceeb27aa617600712a6bd14246
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PatchKernel patch commithttps://git.kernel.org/stable/c/4cefa061fc63f4d2dff5ab4083f43857cd7a2335
Frequently asked questions
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What is CVE-2021-47243?
CVE-2021-47243 is a High severity Linux kernel vulnerability with a CVSS score of 7.1 out of 10 , classified as an Out-of-bounds Read flaw (CWE-125) . CVE-2021-47243 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
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What is the CVSS score for CVE-2021-47243?
CVE-2021-47243 has a CVSS score of 7.1 out of 10, rated High severity (CVSS 3.1). The vector string is
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H. -
Is there a patch available for CVE-2021-47243?
No patch is currently available for CVE-2021-47243. Monitor the NIST NVD and your Linux distribution's security advisories for updates.
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Is CVE-2021-47243 actively exploited?
No — CVE-2021-47243 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.
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What is Out-of-bounds Read (CWE-125)?
The product reads data past the end or before the beginning of the intended buffer. View CWE-125 on MITRE CWE →