CVE-2021-23050Network attack vector

Unauthenticated bd process termination via HTML response

Published Sep 14, 2021 · Updated Aug 3, 2024

Denial of service in F5 BIG-IP Advanced WAF, BIG-IP ASM, and NGINX App Protect allows remote attackers to terminate the bd process. F5 has not disclosed how the HTML response is mishandled; the published record states that processing it causes the bd inspection process to exit. The gate is a CSRF-enabled policy on a virtual server in BIG-IP 15.1.x before 15.1.3 or 16.0.x before 16.0.1.2, or NGINX App Protect before 3.5.0; the documented impact is availability only.

CVSS severity7.5
High
EPSS probability0.47%
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 F5 BIG-IP Advanced WAF, BIG-IP ASM, and NGINX App Protect allows remote attackers to terminate the bd process. F5 has not disclosed how the HTML response is mishandled; the published record states that processing it causes the bd inspection process to exit. The gate is a CSRF-enabled policy on a virtual server in BIG-IP 15.1.x before 15.1.3 or 16.0.x before 16.0.1.2, or NGINX App Protect before 3.5.0; the documented impact is availability only.

The record

CVE
CVE-2021-23050
Published
Sep 14, 2021
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-352, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 14, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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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

7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
5.0NIST NVDAV:N/AC:L/Au:N/C:N/I:N/A:P

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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-352Cross-Site Request Forgery (CSRF)
T1499.004Application or System Exploitation

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

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Your stack

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