Description

Enforce a recursion limit in Unmarshal to prevent stack exhaustion when parsing deeply-nested, recursive structures.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "7.5",
  "pubDate": "2026-08-13T22:17:19.840Z",
  "pubdate": "2026-08-13T22:17:19.840Z",
  "executiveSummary": "This vulnerability involves a stack exhaustion flaw occurring within the Unmarshal function during the parsing of deeply-nested and recursive data structures. The primary weakness stems from a lack of recursion depth limitation when processing hierarchical or recursive inputs. Consequently, an unauthenticated remote attacker capable of supplying maliciously crafted input can trigger uncontrolled recursive function calls, leading to abnormal program termination via stack overflow. The impact of successful exploitation is localized or system-wide denial of service, depending on how the affected component is integrated within broader applications. The risk implication is significant for systems that process untrusted inputs without boundary enforcement, potentially leading to service disruption and application crashes. Exploitation requires the adversary to craft a payload containing excessive nesting depth that exceeds the default call stack limits of the underlying runtime environment. No specialized privileges are required to initiate the attack, provided the parser accepts the targeted input format directly from the network or local interface.",
  "technicalDetails": "The root cause of the vulnerability resides in the recursive descent parsing logic implemented within the Unmarshal function. When handling nested structures, the algorithm invokes itself recursively for each level of hierarchy without maintaining a tracking counter or enforcing a strict maximum recursion threshold. As the parser traverses the input payload, each nested object or array allocation consumes stack frame memory to store local variables, return addresses, and execution context. When an attacker supplies a payload containing thousands of levels of recursive nesting, the cumulative memory consumption of these sequential stack frames rapidly exceeds the allocated stack memory limit designated by the operating system or runtime environment for that execution thread. The vulnerable component is specifically the Unmarshal parsing routine responsible for deserializing complex data types. The attack flow initiates when the target application accepts an untrusted, maliciously crafted payload and passes it directly to the Unmarshal function for processing. As the parser evaluates the deeply-nested structures, the execution enters an uncontrolled sequence of recursive function calls. This behavior continues until the available stack space is completely exhausted, triggering a fatal stack overflow exception that abruptly terminates the host process. The vulnerability affects network-exposed services as well as local utilities that deserialize untrusted data streams. Authentication and privilege requirements depend on the exposure of the vulnerable interface, but the parsing flaw itself is exploitable by any entity capable of submitting arbitrary input structures to the Unmarshal function. Post-exploitation impact is strictly confined to availability disruption, specifically manifesting as a denial of service through application crashes, and does not inherently facilitate remote code execution or unauthorized data access."
}