Client-Side Desynchronization Vulnerability in Member Login Script by PHPJabbers
CVE-2023-53878

7.3HIGH

Key Information:

Vendor

PHPjabbers

Status
Member Login Script
Vendor
CVE Published:
15 December 2025

Badges

👾 Exploit Exists🟡 Public PoC

What is CVE-2023-53878?

The Member Login Script version 3.3 presents a client-side desynchronization vulnerability, where attackers can exploit the parsing of the Content-Length header. By crafting specific POST requests that include smuggled secondary requests, malicious actors can potentially bypass the standard server-side request processing controls, leading to unauthorized access and manipulation of system behaviors.

Affected Version(s)

Member Login Script 3.3

Exploit Proof of Concept (PoC)

PoC code is written by security researchers to demonstrate the vulnerability can be exploited. PoC code is also a key component for weaponization which could lead to ransomware.

CVE-2023-53878 - Proof of Concept

References

https://www.exploit-db.com/exploits/51710
exploit
https://www.phpjabbers.com/member-login-script/
product
https://www.vulncheck.com/advisories/member-login-script-...
third-party-advisory

CVSS V4

Score:
7.3
Severity:
HIGH
Confidentiality:
Low
Integrity:
Low
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • 🟡

    Public PoC available

  • 👾

    Exploit known to exist

  • Vulnerability published

  • Vulnerability Reserved

Credit

nu11secur1ty
JSON
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CVE-2023-53878 : Client-Side Desynchronization Vulnerability in Member Login Script by PHPJabbers