CVE-2023-45612

HIGH

JetBrains Ktor < 2.3.5 - XML External Entity Injection via Default ContentNegotiation

Title source: llm
STIX 2.1

Exploitation Summary

EIP tracks 8 public exploits for CVE-2023-45612. PoCs published by aecelen, infernosalex, bbugdigger.

AI-analyzed exploit summary This repository contains a functional proof-of-concept for CVE-2023-45612, demonstrating an XXE (XML External Entity) vulnerability in Ktor 2.2.3. The PoC includes a server setup and a Python script to test both valid XML and malicious XXE payloads.

Description

In JetBrains Ktor before 2.3.5 default configuration of ContentNegotiation with XML format was vulnerable to XXE

Exploits (8)

nomisec WORKING POC 1 stars
by aecelen · poc
https://github.com/aecelen/ktor-xxe-poc

This repository contains a functional proof-of-concept for CVE-2023-45612, demonstrating an XXE (XML External Entity) vulnerability in Ktor 2.2.3. The PoC includes a server setup and a Python script to test both valid XML and malicious XXE payloads.

Classification
Working Poc 95%
Attack Type
Info Leak
Complexity
Trivial
Reliability
Reliable
Target: Ktor 2.2.3
No auth needed
Prerequisites: Ktor server running with vulnerable configuration · Network access to the target server
devstral-2 · analyzed Feb 19, 2026 Full analysis →
nomisec WORKING POC 1 stars
by infernosalex · poc
https://github.com/infernosalex/CVE-2023-45612-PoC

This repository contains a functional Python script that exploits CVE-2023-45612, an XXE vulnerability in JetBrains Ktor before 2.3.5. The PoC constructs a malicious XML payload to read arbitrary files from the target system via an external entity reference.

Classification
Working Poc 95%
Attack Type
Info Leak
Complexity
Trivial
Reliability
Reliable
Target: JetBrains Ktor < 2.3.5
No auth needed
Prerequisites: Target server running vulnerable Ktor version with XML ContentNegotiation enabled · Network access to the target endpoint
devstral-2 · analyzed Feb 18, 2026 Full analysis →
nomisec WORKING POC 1 stars
by bbugdigger · poc
https://github.com/bbugdigger/ktor-xxe-poc

This repository contains a functional XXE (XML External Entity) exploit PoC for CVE-2023-45612, targeting a Ktor-based application. The Python script sends a crafted XML payload to read arbitrary files from the server.

Classification
Working Poc 95%
Attack Type
Info Leak
Complexity
Trivial
Reliability
Reliable
Target: Ktor (Java/Kotlin web framework)
No auth needed
Prerequisites: Target server running vulnerable Ktor application · Network access to the target server
devstral-2 · analyzed Feb 18, 2026 Full analysis →
nomisec WRITEUP
by stefan-500 · poc
https://github.com/stefan-500/ktor-cve-2023-45612-poc

This repository provides a detailed technical analysis of CVE-2023-45612, an XXE vulnerability in Ktor's ContentNegotiation feature. It includes a description of the root cause, reproduction steps, and prevention guidelines, but lacks functional exploit code.

Classification
Writeup 95%
Attack Type
Info Leak
Complexity
Moderate
Reliability
Theoretical
Target: Ktor versions older than 2.3.5
No auth needed
Prerequisites: Ktor 2.3.4 or earlier with XML ContentNegotiation enabled
devstral-2 · analyzed Feb 19, 2026 Full analysis →
nomisec WORKING POC
by ksaweryr · poc
https://github.com/ksaweryr/CVE-2023-45612-PoC

This repository contains a functional PoC for CVE-2023-45612, demonstrating an XXE vulnerability in Ktor's ContentNegotiation feature. The PoC includes a vulnerable Ktor server and a Python client that exploits the XXE to achieve LFI by reading a file from the server.

Classification
Working Poc 95%
Attack Type
Info Leak
Complexity
Trivial
Reliability
Reliable
Target: Ktor (affected versions with vulnerable ContentNegotiation)
No auth needed
Prerequisites: Docker environment to run the server and client · Network access to the vulnerable Ktor server
devstral-2 · analyzed Feb 19, 2026 Full analysis →
nomisec WORKING POC
by seraphimi · poc
https://github.com/seraphimi/ktor-xxe

This repository contains a functional exploit PoC for CVE-2023-45612, an XXE vulnerability in Ktor's ContentNegotiation XML processing. The PoC includes a Python script that demonstrates both file disclosure and SSRF attacks via crafted XML payloads.

Classification
Working Poc 95%
Attack Type
Info Leak | Ssrf
Complexity
Trivial
Reliability
Reliable
Target: Ktor (ContentNegotiation XML)
No auth needed
Prerequisites: Target server running vulnerable Ktor application with XML ContentNegotiation enabled
devstral-2 · analyzed Feb 19, 2026 Full analysis →
nomisec WORKING POC
by razvanclaudiu · poc
https://github.com/razvanclaudiu/Ktor-XXE-PoC

This repository contains a functional proof-of-concept for CVE-2023-45612, demonstrating an XXE vulnerability in JetBrains Ktor versions before 2.3.5. The PoC includes a vulnerable Ktor server setup and an exploit XML payload to read arbitrary files from the server.

Classification
Working Poc 95%
Attack Type
Info Leak
Complexity
Trivial
Reliability
Reliable
Target: JetBrains Ktor < 2.3.5
No auth needed
Prerequisites: Ktor server with ContentNegotiation plugin and xml() serializer · Ability to send crafted XML payloads to the server
devstral-2 · analyzed Feb 19, 2026 Full analysis →
nomisec WRITEUP
by clemfavre · poc
https://github.com/clemfavre/cve-2023-45612_exploit

This repository provides a detailed technical analysis of CVE-2023-45612, an XXE vulnerability in Ktor's XML serialization. It includes a step-by-step reproduction guide, demonstrating how an attacker can exploit the vulnerability to read sensitive files on the server.

Classification
Writeup 90%
Attack Type
Info Leak
Complexity
Moderate
Reliability
Reliable
Target: Ktor 2.3.4
No auth needed
Prerequisites: A server running Ktor 2.3.4 with XML serialization enabled · Ability to send crafted XML requests to the server
devstral-2 · analyzed Feb 19, 2026 Full analysis →

References (1)

Core 1
Core References

Scores

CVSS v3 8.6
EPSS 0.0060
EPSS Percentile 44.0%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N

CISA SSVC

Vulnrichment
Exploitation none
Automatable yes
Technical Impact partial

Details

CWE
CWE-611
Status published
Products (1)
jetbrains/ktor < 2.3.5
Published Oct 09, 2023
Tracked Since Feb 18, 2026