CVE-2021-23017
A security issue in nginx resolver was identified, which might allow an attacker who is able to forge UDP packets from the DNS server to cause 1-byte memory...
- Published
- Jun 1, 2021
- Updated
- Aug 3, 2024
- Assigning CNA
- f5
- Evidence observed
- Jul 11, 2022
Primary CVSS
nvd · CVSS 3.1
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:LHigh · next 30 days
- Percentile
- 99.0%
- Model date
- Sep 21, 2026
EPSS is a statistical estimate, not a certainty or a measure of impact. Combine it with CVSS, KEV status, exposure and your environment.
Summary
A security issue in nginx resolver was identified, which might allow an attacker who is able to forge UDP packets from the DNS server to cause 1-byte memory overwrite, resulting in worker process crash or potential other impact.
Sources
8- CVE-2021-23017Scanner
NGINX DNS Overflow Vulnerability Check - CVE-2021-23017 PoC
vulnerability in NGINX servers (versions 0.6.18–1.20.0). The scripts aim to cause a Denial of Service (DoS) by sending malicious DNS responses, with enhancements to bypass firewalls.
Proof-of-concept exploit for CVE-2021-23017 targeting a remote host with a custom DNS server. Designed for security testing and vulnerability verification.
Responsible use
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