CVE-2021-47592
5.5 · MEDIUMOverview
CVE-2021-47592 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: stmmac: fix tc flower deletion for VLAN priority Rx steering
To replicate the issue:-
1) Add 1 flower filter for VLAN Priority based frame steering:-
$ IFDEVNAME=eth0
$ tc qdisc add dev $IFDEVNAME ingress
$ tc qdisc add dev $IFDEVNAME root mqprio num_tc 8 \
map 0 1 2 3 4 5 6 7 0 0 0 0 0 0 0 0 \
queues 1@0 1@1 1@2 1@3 1@4 1@5 1@6 1@7 hw 0
$ tc filter add dev $IFDEVNAME parent ffff: protocol 802.1Q \
flower vlan_prio 0 hw_tc 0
2) Get the 'pref' id
$ tc filter show dev $IFDEVNAME ingress
3) Delete a specific tc flower record (say pref 49151)
$ tc filter del dev $IFDEVNAME parent ffff: pref 49151
From dmesg, we will observe kernel NULL pointer ooops
[ 197.170464] BUG: kernel NULL pointer dereference, address: 0000000000000000
[ 197.171367] #PF: supervisor read access in kernel mode
[ 197.171367] #PF: error_code(0x0000) - not-present page
[ 197.171367] PGD 0 P4D 0
[ 197.171367] Oops: 0000 [#1] PREE
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 | >= 5.13, < 5.15.11 | Affected |
Frequently Asked Questions
What is CVE-2021-47592?
CVE-2021-47592 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-2021-47592?
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-2021-47592?
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-2021-47592?
CyberStrike's AI-powered security agents can automatically detect CVE-2021-47592 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.
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