CVE-2021-47592

Kernel crash via invalid tc flower rule

Published Jun 19, 2024 · Updated May 11, 2026

A NULL pointer dereference in Linux kernel 5.13 through 5.15.10 allows local users to crash the kernel through the stmmac driver. tc_del_vlan_flow() obtains a flow_rule from flow_cls_offload_flow_rule() even though that rule is no longer valid during filter deletion, then dereferences its dissector. Reaching the fault requires control of privileged traffic-control settings, a stmmac interface, and VLAN-priority RX steering; deleting the flower filter produces a kernel oops.

CVSS severityUnavailable
Unscored
EPSS probability0.21%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

A NULL pointer dereference in Linux kernel 5.13 through 5.15.10 allows local users to crash the kernel through the stmmac driver. tc_del_vlan_flow() obtains a flow_rule from flow_cls_offload_flow_rule() even though that rule is no longer valid during filter deletion, then dereferences its dissector. Reaching the fault requires control of privileged traffic-control settings, a stmmac interface, and VLAN-priority RX steering; deleting the flower filter produces a kernel oops.

The record

CVE
CVE-2021-47592
Published
Jun 19, 2024
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
Unavailable
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Jun 19, 2024CVE publishedPublication date reported by the CVE source.
  2. May 11, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0e039f5cf86ce2fcb62077a163e7ff3d7b7b7cf3 <97cb5c82aa1dd85a39b1bd021c8b5f18af623779
  2. Affected versionversion=0e039f5cf86ce2fcb62077a163e7ff3d7b7b7cf3 <aeb7c75cb77478fdbf821628e9c95c4baa9adc63
  3. Affected versionversion=5.13

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

The Linux Kernel Organization · Linuxversion=0e039f5cf86ce2fcb62077a163e7ff3d7b7b7cf3 <97cb5c82aa1dd85a39b1bd021c8b5f18af623779; version=0e039f5cf86ce2fcb62077a163e7ff3d7b7b7cf3 <aeb7c75cb77478fdbf821628e9c95c4baa9adc63; version=5.13

Published CVSS scores

No CVSS assessment is available in this record.

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

No sourced classifications are available.

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo