CVE-2020-5876Network attack vector

Configuration disclosure via unencrypted peer connections

Published Apr 30, 2020 · Updated Aug 4, 2024

Cleartext transmission in F5 Networks BIG-IP allows attackers to intercept configuration data through a spoofed ConfigSync peer. A race between mcpd and related processes causes initial connections to a new ConfigSync peer to be sent without encryption. Exploitation requires network access while a peer address is changed, a peer is added, or TMM starts; intercepted traffic can expose sensitive configuration data.

CVSS severity8.1
High
EPSS probability0.59%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cleartext transmission in F5 Networks BIG-IP allows attackers to intercept configuration data through a spoofed ConfigSync peer. A race between mcpd and related processes causes initial connections to a new ConfigSync peer to be sent without encryption. Exploitation requires network access while a peer address is changed, a peer is added, or TMM starts; intercepted traffic can expose sensitive configuration data.

The record

CVE
CVE-2020-5876
Published
Apr 30, 2020
Updated
Aug 4, 2024
Vendor
F5 Networks
Product
BIG-IP
Classifications
CWE-319, CWE-362, T1557
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 30, 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

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=15.0.0-15.0.1.3, 14.1.0-14.1.2.3, 13.1.0-13.1.3.3, 12.1.0-12.1.5.1, 11.6.1-11.6.5.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

F5 Networks · BIG-IPversion=15.0.0-15.0.1.3, 14.1.0-14.1.2.3, 13.1.0-13.1.3.3, 12.1.0-12.1.5.1, 11.6.1-11.6.5.1

Published CVSS scores

8.1NIST NVDCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
6.8NIST NVDAV:N/AC:M/Au:N/C:P/I:P/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 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 exploitUnconfirmed

Weakness, pattern, technique

CWE-319Cleartext Transmission of Sensitive Information
CWE-362Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
T1557Adversary-in-the-Middle

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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