CVE-2002-20001Dheater Denial of Service
The Diffie-Hellman Key Agreement Protocol allows remote attackers (from the client side) to send arbitrary numbers that are actually not public keys, and trigger expensive server-side DHE modular-exponentiation calculations, aka a D(HE)at or D(HE)ater attack.
Published Nov 11, 2021 · Updated Sep 23, 2026
Key Facts
Patch in the next maintenance window- CVE-2002-20001 is a high-severity vulnerability (CVSS 7.5 v3.1) affecting Dheater (Balasys), Big-Ip Access Policy Manager (F5), Big-Ip Advanced Firewall Manager (F5) and 22 more products.
- It is not listed in any known-exploited vulnerabilities catalog. No public exploit code is known.
- EPSS estimates a 25% probability of exploitation in the next 30 days.
- Fixed versions are available, including Big-Ip Access Policy Manager 16.1.4, Big-Ip Access Policy Manager 17.1.0, Big-Ip Advanced Firewall Manager <=17.1.2.
- Brandefense priority: patch in the next maintenance window, because of its high severity, although no exploitation is known.
Scores
CVSS v3.1
7.5
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS (30-day exploit likelihood)
25%
Higher than 97.8% of all scored CVEs
Exploit maturity
None known
ATLAS score
36/100
Publication score, see How it works
Exploitation Verdict
KEV listed
Not listed
Federal due date
None
No federal due date
Ransomware use
Not reported
Attributed actors
None named
Exploit & Defence Guidance
Exploit maturity
None known
Public exploit code
0
Proof-of-concept links
In-the-wild evidence
1
Reports of active use
Advisories And Exploit References
Description
The Diffie-Hellman Key Agreement Protocol allows remote attackers (from the client side) to send arbitrary numbers that are actually not public keys, and trigger expensive server-side DHE modular-exponentiation calculations, aka a D(HE)at or D(HE)ater attack. The client needs very little CPU resources and network bandwidth.
The attack may be more disruptive in cases where a client can require a server to select its largest supported key size. The basic attack scenario is that the client must claim that it can only communicate with DHE, and the server must be configured to allow DHE.
Affected Products
66 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| DheaterBalasys | See advisory | n/a |
| Big-Ip Access Policy ManagerF5 | See advisory | 16.1.4 |
| Big-Ip Advanced Firewall ManagerF5 | 17.5.0 | 17.1.2 |
| Big-Ip Advanced Web Application FirewallF5 | 17.5.0 | 17.1.2 |
| Big-Ip AnalyticsF5 | 17.5.0 | 17.1.2 |
Patched Releases
Big-Ip Access Policy Manager
16.1.4, 17.1.0
Big-Ip Advanced Firewall Manager
<=17.1.2
Big-Ip Advanced Web Application Firewall
<=17.1.2
Big-Ip Analytics
<=17.1.2
Big-Ip Application Acceleration Manager
<=17.1.2
Big-Ip Application Security Manager
<=17.1.2
Big-Ip Application Visibility And Reporting
<=17.1.2
Big-Ip Carrier-Grade Nat
<=17.1.2
Big-Ip Ddos Hybrid Defender
<=17.1.2
Big-Ip Domain Name System
<=17.1.2
Big-Ip Edge Gateway
<=17.1.2
Big-Ip Fraud Protection Service
<=17.1.2
Big-Ip Global Traffic Manager
<=17.1.2
Big-Ip Link Controller
<=17.1.2
Big-Ip Local Traffic Manager
<=17.1.2
Big-Ip Policy Enforcement Manager
<=17.1.2
Big-Ip SSL Orchestrator
<=17.1.2
Big-Ip Webaccelerator
<=17.1.2
Big-Ip Websafe
<=17.1.2
Big-Iq Centralized Management
<=8.4.0
f5 f5os-a
<=1.3.2
f5 f5os-c
<=1.3.2
hpe arubaos-cx
10.06.0180, 10.07.0030, 10.08.0010, 10.09.0002
libopenssl-1_1-devel
1.1.1m-4.1
libopenssl-1_1-devel-32bit
1.1.1m-4.1
Timeline
Publicly disclosed
Nov 11, 2021
Last updated
Sep 23, 2026
Weakness Type
- CWE-400 Uncontrolled Resource Consumption
References
- advisorycert-portal.siemens.com · ssa-506569.pdf
- advisorydheatattack.com
- advisorydheatattack.gitlab.io
- advisorygithub.com · dheater
- advisorygitlab.com · dheater
FAQ
Common Questions.
The Diffie-Hellman Key Agreement Protocol allows remote attackers (from the client side) to send arbitrary numbers that are actually not public keys, and trigger expensive server-side DHE modular-exponentiation calculations, aka a D(HE)at or D(HE)ater attack.
Affected: Dheater (Balasys); Big-Ip Access Policy Manager (F5); Big-Ip Advanced Firewall Manager (F5) versions 17.5.0, among others. The full list is in the CVE brief.
It is not listed in any known-exploited vulnerabilities catalog.
No, it is not currently listed in the CISA Known Exploited Vulnerabilities catalog.
No public exploit code is known.
Fixed versions are available, including Big-Ip Access Policy Manager 16.1.4, Big-Ip Access Policy Manager 17.1.0, Big-Ip Advanced Firewall Manager <=17.1.2.
Brandefense priority: patch in the next maintenance window, because of its high severity, although no exploitation is known.
Is CVE-2002-20001 On Your Attack Surface?
Brandefense matches it against the products discovered on your perimeter and opens a finding the day a CVE like this is listed.
Request A Demo