CVE-2021-34586— CODESYS V2 web server: crafted requests could trigger a null pointer dereference (DoS)
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I. Basic Information for CVE-2021-34586
Vulnerability Information
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Vulnerability Title
CODESYS V2 web server: crafted requests could trigger a null pointer dereference (DoS)
Source: NVD (National Vulnerability Database)
Vulnerability Description
In the CODESYS V2 web server prior to V1.1.9.22 crafted web server requests may cause a Null pointer dereference in the CODESYS web server and may result in a denial-of-service condition.
Source: NVD (National Vulnerability Database)
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Source: NVD (National Vulnerability Database)
Vulnerability Type
空指针解引用
Source: NVD (National Vulnerability Database)
Vulnerability Title
CODESYS 代码问题漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
CODESYS是德国3S-Smart Software Solutions的一套控制器开发系统 CODESYS V2 web server 1.1.9.22 之前版本存在代码问题漏洞，该漏洞源于在web服务器中，精心制作的web服务器请求可能会导致CODESYS web服务器中的空指针解引用，并可能导致拒绝服务。
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)
Affected Products
| Vendor | Product | Affected Versions | CPE | Subscribe |
|---|---|---|---|---|
| CODESYS | CODESYS V2 | all web servers ~ V1.1.9.22 | - |
II. Public POCs for CVE-2021-34586
| # | POC Description | Source Link | Shenlong Link |
|---|
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- https://www.tenable.com/security/research/tra-2021-47x_refsource_MISC
- https://nvd.nist.gov/vuln/detail/CVE-2021-34586
Same Patch Batch · CODESYS · 2021-10-26 · 7 CVEs total
| CVE-2021-34584 | 9.1 CRITICAL | CODESYS V2 web server: crafted requests could trigger a buffer over-read (DoS) |
| CVE-2021-34595 | 8.1 HIGH | CODESYS V2 runtime: out-of-bounds read or write access may result in denial-of-service |
| CVE-2021-34593 | 7.5 HIGH | CODESYS V2 runtime: unauthenticated invalid requests may result in denial-of-service |
| CVE-2021-34585 | 7.5 HIGH | CODESYS V2 web server: crafted requests could trigger a pointer dereference with an invali |
| CVE-2021-34583 | 7.5 HIGH | CODESYS V2 web server: crafted requests could trigger a heap-based buffer overflow (DoS) |
| CVE-2021-34596 | 6.5 MEDIUM | CODESYS V2 runtime: Access of Uninitialized Pointer may result in denial-of-service |
IV. Related Vulnerabilities
Same product: CODESYS V2
- CVE-2021-34596
CODESYS V2 runtime: Access of Uninitialized Pointer may resu - CVE-2021-34595
CODESYS V2 runtime: out-of-bounds read or write access may r - CVE-2021-34593
CODESYS V2 runtime: unauthenticated invalid requests may res - CVE-2021-34585
CODESYS V2 web server: crafted requests could trigger a poin - CVE-2021-34584
CODESYS V2 web server: crafted requests could trigger a buff
Same vendor: CODESYS
- CVE-2026-35225
Improper timeout handling in CODESYS EtherNetIP - CVE-2026-3509
CODESYS Control Audit Log Format String DoS - CVE-2025-41660
CODESYS Control Boot Application Replacement Enables Code Ex - CVE-2026-2364
CODESYS Installer TOCTOU Privilege Escalation - CVE-2025-41700
CODESYS Development System - Deserialization of Untrusted Da
Same weakness: CWE-476
- CVE-2026-8252
Open5GS SMF smf_nsmf_handle_create_data_in_hsmf null pointer - CVE-2026-7259
Null pointer dereference in php_mb_check_encoding() via mb_e - CVE-2026-7262
NULL pointer dereference in SOAP apache:Map decoder with mis - CVE-2026-42183
Argo Workflows: SSO RBAC Delegation Nil Pointer Dereference - CVE-2026-6666
PgBouncer crash in kill_pool_logins_server_error
V. Comments for CVE-2021-34586
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