CVE-2020-5859Network attack vector

Remote service interruption via malformed HTTP/3 messages

Published Mar 27, 2020 · Updated Aug 4, 2024

Denial of service in F5 Networks BIG-IP 15.1.0.1 allows remote attackers to crash TMM with specially formatted HTTP/3 messages. TMM's HTTP/3 processing path accepts the malformed message and produces a core file, but F5 has not disclosed the defective operation. The target must expose an HTTP/3 virtual server, and the resulting TMM crash interrupts traffic processing.

CVSS severity7.5
High
EPSS probability1.04%
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 Networks BIG-IP 15.1.0.1 allows remote attackers to crash TMM with specially formatted HTTP/3 messages. TMM's HTTP/3 processing path accepts the malformed message and produces a core file, but F5 has not disclosed the defective operation. The target must expose an HTTP/3 virtual server, and the resulting TMM crash interrupts traffic processing.

The record

CVE
CVE-2020-5859
Published
Mar 27, 2020
Updated
Aug 4, 2024
Vendor
F5 Networks
Product
BIG-IP
Classifications
T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 27, 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=15.1.0.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

F5 Networks · BIG-IPversion=15.1.0.1

Published CVSS scores

7.5TenableCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
5.0TenableAV: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

T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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