Ktor
CVE-2019-19703
MEDIUM
Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A01:2025 - Broken Access Control
ASVS 5.0
V3 - Web Frontend Security Redirect URL validation
MITRE ATT&CK
1 technique across 1 tactic: Initial Access The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. |
| Impact | CVSS score of 6.1 (MEDIUM). Attack characteristics: network attack vector, low complexity, no privileges required, user interaction required. Public proof-of-concept exploit code is available. |
| Exploit ScenarioDerived | A remote attacker could redirect users to malicious websites via URL manipulation by sending crafted requests to the affected application. No authentication is required to exploit this vulnerability. |
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Alert meAnalysisAI
In Ktor through 1.2.6, the client resends data from the HTTP Authorization header to a redirect location. Rated medium severity (CVSS 6.1), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.
RemediationAI
No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Validate redirect destinations against an allowlist, avoid using user input in redirect URLs.
Affected Packages
Source: OSV (Open Source Vulnerabilities)
Affects your stack
Affects 1 package in maven
Checking this CVE against your own stacks and servers is part of the Basic plan and up.
Technical ContextAI · show details
This vulnerability is classified as Open Redirect (CWE-601), which allows attackers to redirect users to malicious websites via URL manipulation. In Ktor through 1.2.6, the client resends data from the HTTP Authorization header to a redirect location. Affected products include: Jetbrains Ktor. Version information: through 1.2.6.
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- Exploit and PoC references, threat intelligence from 22 sources
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Severity by source
AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Primary rating from NVD · only source for this CVE.
CVSS VectorNVD
DescriptionNVD
In Ktor through 1.2.6, the client resends data from the HTTP Authorization header to a redirect location.
Threat Intelligence Overview
NVD
CVE.org
EPSS
GitHub
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Affected Products (CPE)NVD
In JetBrains Ktor before 2.3.5 default configuration of ContentNegotiation with XML format was vulnerable to XXE. Rated
JetBrains Ktor framework before 1.2.0-rc does not sanitize the username provided by the user for the LDAP protocol, lead
JetBrains Ktor framework before version 1.2.6 was vulnerable to HTTP Response Splitting. Rated medium severity (CVSS 5.4
In JetBrains Ktor before 2.3.5 server certificates were not verified. Rated critical severity (CVSS 9.1), this vulnerabi
JetBrains Ktor framework (created using the Kotlin IDE template) versions before 1.1.0 were resolving artifacts using an
In JetBrains Ktor before 1.6.4, nonce verification during the OAuth2 authentication process is implemented improperly. R
In Ktor before 1.3.0, request smuggling is possible when running behind a proxy that doesn't handle Content-Length and T
In JetBrains Ktor before 2.1.0 the wrong authentication provider could be selected in some cases. Rated medium severity
In JetBrains Ktor before 1.4.1, HTTP request smuggling was possible. Rated medium severity (CVSS 6.5), this vulnerabilit
JetBrains Ktor before 2.1.0 was vulnerable to the Reflect File Download attack. Rated medium severity (CVSS 6.1), this v
In JetBrains Ktor before 3.1.1 an HTTP Request Smuggling was possible. Rated medium severity (CVSS 5.3), this vulnerabil
In JetBrains Ktor before 2.3.13 improper caching in HttpCache Plugin could lead to response information disclosure. Rate
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