CVE-2019-1010183 in serde_yaml
Summary
by MITRE
serde serde_yaml 0.6.0 to 0.8.3 is affected by: Uncontrolled Recursion. The impact is: Denial of service by aborting. The component is: from_* functions (all deserialization functions). The attack vector is: Parsing a malicious YAML file. The fixed version is: 0.8.4 and later.
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Analysis
by VulDB Data Team • 11/07/2023
The vulnerability identified as CVE-2019-1010183 affects the serde_yaml Rust crate version 0.6.0 through 0.8.3, representing a critical uncontrolled recursion flaw that can lead to denial of service conditions. This issue specifically impacts the deserialization functions within the crate, particularly those prefixed with "from_" which handle YAML parsing operations. The vulnerability stems from insufficient recursion depth limits during YAML parsing, allowing maliciously crafted input to trigger infinite recursive calls that ultimately abort the application process.
The technical flaw manifests when the serde_yaml crate processes YAML files containing deeply nested structures or circular references without proper recursion guards. Attackers can exploit this by crafting malicious YAML documents that contain recursive data structures or excessive nesting levels, causing the deserialization functions to consume excessive memory and processing resources until the application terminates. This behavior aligns with CWE-674, which categorizes uncontrolled recursion as a weakness that can lead to resource exhaustion and system instability. The vulnerability affects all deserialization functions within the crate, making it particularly dangerous as any application using serde_yaml for YAML processing becomes susceptible to this attack vector.
The operational impact of this vulnerability extends beyond simple denial of service, as it can affect any system or application that relies on serde_yaml for processing external YAML data. Applications using this crate for configuration parsing, data interchange, or any scenario involving untrusted YAML input become vulnerable to attacks that can cause complete service disruption. The attack vector is straightforward and requires only the creation of a malicious YAML file that triggers the recursive parsing behavior. This makes the vulnerability particularly dangerous in environments where YAML files might be processed from untrusted sources, such as web applications accepting user-uploaded configuration files or systems processing data from external APIs. The vulnerability also aligns with ATT&CK technique T1499.004, which covers network denial of service attacks through resource exhaustion, as the recursive behavior consumes system resources until the application aborts.
The remediation for CVE-2019-1010183 requires upgrading to version 0.8.4 or later of the serde_yaml crate, which implements proper recursion depth limiting and prevents the infinite recursive calls that previously caused system aborts. Organizations should prioritize this upgrade across all affected systems and applications, particularly those handling external YAML input. Additionally, implementing input validation and sanitization measures for YAML processing can provide additional defense-in-depth layers. Security teams should monitor for any applications that might be using older versions of the crate through dependency trees or transitive dependencies, as the vulnerability can persist even when the primary application is updated if underlying libraries remain vulnerable. The fix demonstrates proper implementation of recursion limits that prevent resource exhaustion while maintaining functionality for legitimate YAML parsing operations, addressing the core issue without breaking existing use cases.