CVE-2021-47595
5.5 · MEDIUMOverview
CVE-2021-47595 is a medium-severity vulnerability affecting linux linux_kernel. It was published on June 19, 2024 and has a CVSS 3.1 base score of 5.5 (MEDIUM).
This vulnerability has a CVSS 3.1 base score of 5.5, rated MEDIUM. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.
Technical Description
In the Linux kernel, the following vulnerability has been resolved:
net/sched: sch_ets: don't remove idle classes from the round-robin list
Shuang reported that the following script:
1) tc qdisc add dev ddd0 handle 10: parent 1: ets bands 8 strict 4 priomap 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7
2) mausezahn ddd0 -A 10.10.10.1 -B 10.10.10.2 -c 0 -a own -b 00:c1:a0:c1:a0:00 -t udp &
3) tc qdisc change dev ddd0 handle 10: ets bands 4 strict 2 quanta 2500 2500 priomap 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3
crashes systematically when line 2) is commented:
list_del corruption, ffff8e028404bd30->next is LIST_POISON1 (dead000000000100)
------------[ cut here ]------------
kernel BUG at lib/list_debug.c:47!
invalid opcode: 0000 [#1] PREEMPT SMP NOPTI
CPU: 0 PID: 954 Comm: tc Not tainted 5.16.0-rc4+ #478
Hardware name: Red Hat KVM, BIOS 1.11.1-4.module+el8.1.0+4066+0f1aadab 04/01/2014
RIP: 0010:__list_del_entry_valid.cold.1+0x12/0x47
Code: fe ff 0f 0b 48 89 c1 4c 89 c6 48 c7 c7 08 42 1b 87
Remediation
Check the references section for vendor advisories and patches from linux. Update linux_kernel to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected Products
| Vendor | Product | Versions | Status |
|---|---|---|---|
| linux | linux_kernel | >= 5.10.83, < 5.10.88 | Affected |
References
Frequently Asked Questions
What is CVE-2021-47595?
CVE-2021-47595 is a medium-severity vulnerability affecting linux linux_kernel. It was published on June 19, 2024 and has a CVSS 3.1 base score of 5.5 (MEDIUM).
How severe is CVE-2021-47595?
This vulnerability has a CVSS 3.1 base score of 5.5, rated MEDIUM. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.
How do I fix or remediate CVE-2021-47595?
Check the references section for vendor advisories and patches from linux. Update linux_kernel to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2021-47595?
CyberStrike's AI-powered security agents can automatically detect CVE-2021-47595 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
How CyberStrike Helps
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