CVE-2021-34173Public exploitNetwork attack vector

Kernel panic via malformed beacon CSA frame

Published Jul 14, 2021 · Updated Aug 4, 2024

Denial of service in Espressif ESP32 firmware 4.2 and earlier allows remote attackers to trigger a kernel panic via a malformed beacon CSA frame. The public record identifies the beacon's Channel Switch Announcement frame as malformed input but does not disclose the faulty parser operation. An unauthenticated attacker able to transmit Wi-Fi management frames can crash the device, and service remains unavailable until it is rebooted.

CVSS severity7.5
High
EPSS probability1.47%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Espressif ESP32 firmware 4.2 and earlier allows remote attackers to trigger a kernel panic via a malformed beacon CSA frame. The public record identifies the beacon's Channel Switch Announcement frame as malformed input but does not disclose the faulty parser operation. An unauthenticated attacker able to transmit Wi-Fi management frames can crash the device, and service remains unavailable until it is rebooted.

The record

CVE
CVE-2021-34173
Published
Jul 14, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 14, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record 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?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.5NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
7.8NVDAV:N/AC:L/Au:N/C:N/I:N/A:C

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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

T1499.004Endpoint Denial of Service Application or System Exploitation

Public exploit references

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

Technologies

Your stack

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Your stack

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