[MAVEN:GHSA-FMM9-3GV8-58F4] Improper Handling of Missing Values in kaml
Impact
Attackers that could provide arbitrary YAML input to an application that uses kaml could cause the application to endlessly loop while parsing the input. This could result in resource starvation and denial of service.
This only affects applications that use polymorphic serialization with the default tagged polymorphism style. Applications using the property polymorphism style are not affected.
YAML input for a polymorphic type that provided a tag but no value for the object would trigger the issue, for example:
yaml
!<x>
The following is a sample application that demonstrates this issue:
```kotlin
import com.charleskorn.kaml.Yaml
import kotlinx.serialization.SerialName
import kotlinx.serialization.Serializable
@Serializable
private sealed class K {
@Serializable
@SerialName("x")
data class X(
val property: String? = null,
) : K()
}
const val s = """
!<x>
"""
fun main() {
println("Started.")
val result = Yaml.default.decodeFromString(K.serializer(), s)
println("Finished, result is $result")
}
```
On vulnerable versions of kaml, the decodeFromString()
operation hangs and never returns.
Patches
Version 0.35.3 or later contain the fix for this issue.
Package | Affected Version |
---|---|
pkg:maven/com.charleskorn.kaml/kaml | < 0.35.2 |
Package | Fixed Version |
---|---|
pkg:maven/com.charleskorn.kaml/kaml | = 0.35.3 |
- ID
- MAVEN:GHSA-FMM9-3GV8-58F4
- Severity
- moderate
- URL
- https://github.com/advisories/GHSA-fmm9-3gv8-58f4
- Published
-
2021-09-07T23:08:40
(3 years ago) - Modified
-
2023-02-01T05:06:25
(19 months ago) - Rights
- Maven Security Team
# CVE | Description | CVSS | EPSS | EPSS Trend (30 days) | Affected Products | Weaknesses | Security Advisories | Exploits | PoC | Pubblication Date | Modification Date |
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# CVE | Description | CVSS | EPSS | EPSS Trend (30 days) | Affected Products | Weaknesses | Security Advisories | PoC | Pubblication Date | Modification Date |