CVE-2021-23017
Quick assessment
Affected
n/a Nginx Web Server, Nginx Plus
Exploitation
Public or AI PoC available; prioritize validation
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.
F5 NGINX Controller是美国F5公司的一款用于NGINX的集中式监视和管理平台。该平台支持使用可视化界面管理多个NGINX实例。 F5 NGINX Controller存在安全漏洞，该漏洞允许攻击者从DNS服务器伪造UDP数据包造成1-byte的内存覆盖，导致工作进程崩溃或潜在的其他影响。
Public Exploits 1
ExploitDB · 1
EDB-50973 [remote]
Possible ATT&CK Techniques 1 AI
T1498 · Network Denial of Service
Get alerts for future matching vulnerabilities
Log in to subscribe
I. Basic Information for CVE-2021-23017
Vulnerability Information
Have questions about the vulnerability? See if Shenlong's analysis helps!
View Shenlong Deep Dive ↗
Although we use advanced large model technology, its output may still contain inaccurate or outdated information.Shenlong tries to ensure data accuracy, but please verify and judge based on the actual situation.
Vulnerability Title
N/A
Source: CVE Program / CVE List V5
Vulnerability Description
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.
Source: CVE Program / CVE List V5
CVSS Information
N/A
Source: CVE Program / CVE List V5
Vulnerability Type
Off-by-one错误
Source: CVE Program / CVE List V5
Vulnerability Title
F5 NGINX Controller 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
F5 NGINX Controller是美国F5公司的一款用于NGINX的集中式监视和管理平台。该平台支持使用可视化界面管理多个NGINX实例。 F5 NGINX Controller存在安全漏洞，该漏洞允许攻击者从DNS服务器伪造UDP数据包造成1-byte的内存覆盖，导致工作进程崩溃或潜在的其他影响。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)
Shenlong Deep Dive — AI Deep Analysis
10-question deep dive: root cause, exploitation, mitigation, urgency. Read summary free, full version requires login.
Affected Products
| Vendor | Product | Affected Versions | CPE | Subscribe |
|---|---|---|---|---|
| - | Nginx Web Server, Nginx Plus | Nginx Web Server versions 0.6.18 thru 1.20.0 before 1.20.1, Nginx plus versions R13 thru R23 before R23 P1. Nginx plus version R24 before R24 P1 | - |
|
II. Public POCs for CVE-2021-23017
| # | POC Description | Source Link | Shenlong Link |
|---|---|---|---|
| 1 | nginx 1.15.10 patch against cve-2021-23017 (ingress version) | https://github.com/niandy/nginx-patch | POC Details |
| 2 | PoC for Nginx 0.6.18 - 1.20.0 Memory Overwrite Vulnerability CVE-2021-23017 | https://github.com/M507/CVE-2021-23017-PoC | POC Details |
| 3 | None | https://github.com/lakshit1212/CVE-2021-23017-PoC | POC Details |
| 4 | None | https://github.com/ShivamDey/CVE-2021-23017 | POC Details |
| 5 | The issue only affects nginx if the "resolver" directive is used in the configuration file. Further, the attack is only possible if an attacker is able to forge UDP packets from the DNS server. | https://github.com/z3usx01/CVE-2021-23017-POC | POC Details |
| 6 | None | https://github.com/lukwagoasuman/-home-lukewago-Downloads-CVE-2021-23017-Nginx-1.14 | POC Details |
| 7 | NGINX Security Hardening & Vulnerability Remediation Analysis of critical CVEs (CVE-2021-23017, HTTP/2 DoS flaws) in outdated NGINX versions, with actionable steps for mitigation: upgrades, HTTP/2 hardening, and patch automation. Includes Nessus scan validation and proactive monitoring strategies. | https://github.com/Cybervixy/Vulnerability-Management | POC Details |
| 8 | NGINX DNS Overflow Vulnerability Check - CVE-2021-23017 PoC | https://github.com/moften/CVE-2021-23017 | POC Details |
| 9 | 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. | https://github.com/6lj/EVIL-CVE-2021-23017-Update-2025 | POC Details |
AI-Generated POC
Premium
No public POC found.
Login to generate AI POCIII. Intelligence Information for CVE-2021-23017
请登录查看更多情报信息。
Vendor Advisories for CVE-2021-23017 (5)
-
https://support.f5.com/csp/article/K12331123%2C x_refsource_MISC
-
https://www.oracle.com/security-alerts/cpujan2022.html x_refsource_MISC
-
https://www.oracle.com/security-alerts/cpuoct2021.html x_refsource_MISC
-
https://security.netapp.com/advisory/ntap-20210708-0006/ x_refsource_CONFIRM
-
https://www.oracle.com/security-alerts/cpuapr2022.html x_refsource_MISC
Exploits & Public PoCs for CVE-2021-23017 (1)
Mailing List Discussions for CVE-2021-23017 (6)
-
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/7SFVYHC7OXTEO4SMBWXDVK6E5IMEYMEE/ vendor-advisory x_refsource_FEDORA
Other References for CVE-2021-23017 (1)
-
http://mailman.nginx.org/pipermail/nginx-announce/2021/000300.html x_refsource_MISC
Same Patch Batch · n/a · 2021-06-01 · 38 CVEs total
| CVE-2020-27748 | xdg-utils 安全漏洞 | |
| CVE-2020-26669 | Fastspot BigTree 跨站脚本漏洞 | |
| CVE-2020-26668 | Fastspot BigTree SQL注入漏洞 | |
| CVE-2021-31641 | CHIYU科技BF-630W 跨站脚本漏洞 | |
| CVE-2021-3412 | 3Scale 安全漏洞 | |
| CVE-2021-3516 | libxml2 资源管理错误漏洞 | |
| CVE-2021-20306 | Red Hat BPMN Editor 安全漏洞 | |
| CVE-2021-3515 | PostgreSQL 操作系统命令注入漏洞 | |
| CVE-2021-3495 | Kiali-operator 安全漏洞 | |
| CVE-2021-3543 | Red Hat, Inc. Nitro Enclaves内核驱动 资源管理错误漏洞 | |
| CVE-2020-26670 | Fastspot BigTree 操作系统命令注入漏洞 | |
| CVE-2021-23021 | F5 NGINX Controller 安全漏洞 | |
| CVE-2021-23020 | NGINX控制器 安全特征问题漏洞 | |
| CVE-2021-23019 | F5 NGINX Controller 安全漏洞 | |
| CVE-2021-23018 | Nginx 控制器 安全漏洞 | |
| CVE-2021-27828 | In4Velocity In4Suite ERP SQL注入漏洞 | |
| CVE-2021-25932 | Opennms Group OpenNMS 跨站脚本漏洞 | |
| CVE-2021-31684 | Github json-smart-v1 缓冲区错误漏洞 | |
| CVE-2021-32027 | PostgreSQL 输入验证错误漏洞 | |
| CVE-2021-3424 | Red Hat Single Sign-On 7安全漏洞 |
Showing top 20 of 38 CVEs. View all on vendor page → →
IV. Related Vulnerabilities
Same vendor: n/a
-
CVE-2026-103227
GPAC DASH Client dash_client.c gf_dash_resolve_url buffer ov -
CVE-2026-103118
GraphicsMagick WPG File wpg.c ExtractPostscript recursion -
CVE-2026-102249
REBUILD file-editor-save authorization -
CVE-2026-102248
Rebuild Login Endpoint login improper authentication -
CVE-2026-102247
FastAdmin Database Management database.php unnecessary privi
Same weakness: CWE-193
-
CVE-2026-101014
Trusted Domain Project OpenDMARC DMARC Record opendmarc_util -
CVE-2026-100889
Trusted Domain Project OpenDKIM Decoder util.c dkim_qp_decod -
CVE-2026-18460
Off-by-one Error, Out-of-bounds Write vulnerability in RTI C -
CVE-2026-83600
Netdata: Streaming protocol chart slot guard off-by-one allo -
CVE-2026-76081
ZITADEL: Improper Role Revocation on Granted Projects during
V. Comments for CVE-2021-23017
No comments yet