CVE-2020-5853Network attack vector

Authenticated cross-site scripting via portal rewrite conflict

Published Jan 14, 2020 · Updated Aug 4, 2024

Cross-site scripting in F5 BIG-IP Access Policy Manager portal access allows remote authenticated users to run script in users' browsers. The portal rewrite engine fails to keep internal access names distinct while rewriting crafted backend JavaScript; F5 has not disclosed the responsible function. Exploitation requires authenticated portal access, a crafted backend response, and user interaction, and permits browser-context data access or modification.

CVSS severity5.4
Medium
EPSS probability0.52%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cross-site scripting in F5 BIG-IP Access Policy Manager portal access allows remote authenticated users to run script in users' browsers. The portal rewrite engine fails to keep internal access names distinct while rewriting crafted backend JavaScript; F5 has not disclosed the responsible function. Exploitation requires authenticated portal access, a crafted backend response, and user interaction, and permits browser-context data access or modification.

The record

CVE
CVE-2020-5853
Published
Jan 14, 2020
Updated
Aug 4, 2024
Vendor
F5 Networks
Product
BIG-IP Access Policy Manager
Classifications
CWE-79, T1189
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jan 14, 2020CVE 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

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Is a vulnerable build present?

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

  1. Affected versionversion=11.5.2-11.6.5.1
  2. Affected versionversion=12.1.0-12.1.5
  3. Affected versionversion=13.1.0-13.1.3.2
  4. Affected versionversion=14.0.0-14.1.2.3
  5. Affected versionversion=15.0.0-15.1.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

F5 Networks · BIG-IP Access Policy Managerversion=11.5.2-11.6.5.1; version=12.1.0-12.1.5; version=13.1.0-13.1.3.2; version=14.0.0-14.1.2.3; version=15.0.0-15.1.0

Published CVSS scores

3.5NIST NVDAV:N/AC:M/Au:S/C:N/I:P/A:N
5.4NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1189Drive-by Compromise

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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