External risk intelligence

pyquokka FlightServer Pickle Deserialization RCE.

CVE advisorySeverity: CRITICAL (CVSS 9.8)

CVE-2025-62515

The vulnerability exists in a data lake framework component (FlightServer). While the documentation notes that the service can be configured to listen on 0.0.0.0, exposing it to the network, this framework is typically used for internal data processing or analytical tasks rather than being an internet-facing web service or edge gateway by default. Public exposure is possible through misconfiguration but not a standard deployment pattern.

Deserialization

Halo Surface Signal: 3 out of 5 — possibly public-facing.

External exposure likelihood

Horizon Alert

Summary of the vulnerability and why it matters

A critical vulnerability has been identified in the pyquokka framework, which is used for time-series data lakes. The issue, stemming from the direct deserialization of data without proper checks, could allow unauthenticated attackers to execute arbitrary code remotely on affected systems. While the framework's typical use cases may limit direct exposure, misconfiguration could expose it to network-wide attacks.

Unchecked data handling enables remote code execution.
Critical risk if the data lake framework is exposed.
Assess and confirm relevance to our deployed systems.

Attack Path

How an attacker could exploit the issue

An attacker can reach and trigger this vulnerability by sending specially crafted data to a network-accessible FlightServer. If the server is exposed to the network, attackers can send malicious pickled payloads through the `set_configs` action, potentially leading to arbitrary remote code execution. Similar risks exist in other functions that deserialize untrusted data using pickle.loads.

Server accessible on the network.
Send malicious pickled data via `set_configs`.
Arbitrary remote code execution.

Live Threat

Current exploitation, exposure, and threat context

The pyquokka FlightServer, when configured to listen publicly, could allow network attackers to execute arbitrary code by sending specially crafted data through its action interface. This risk extends to other functions that deserialize untrusted data using pickle.

Arbitrary code execution.
Malicious payloads sent over the network.
Compromise of the affected system.

Operational Fix

Recommended remediation, mitigation, and detection steps

The pyquokka framework's FlightServer component, when configured to listen on all interfaces, is vulnerable to remote code execution due to deserialization of untrusted data using `pickle.loads()`. Platform or data engineering teams responsible for the pyquokka deployment should first identify all instances of the affected FlightServer, determine their network reachability and criticality, and then establish ownership for remediation planning.

Platform or data engineering teams own remediation.
Verify FlightServer network reachability and criticality.
Plan risk-based remediation actions.

Supplementary metadata

CVSS vector

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Frequently asked questions

What is pyquokka and how is it used?

pyquokka is a software framework designed to enable data lakes to handle time-series data efficiently. It is primarily utilized by data engineering and analytical teams for high-performance data processing tasks. In this architecture, components like the FlightServer act as interfaces to manage data flow and configurations within those analytics environments.

What does CWE-502 mean regarding CVE-2025-62515?

CWE-502 refers to Deserialization of Untrusted Data. This is a security flaw where an application takes complex data received from an outside source and converts it into a live object without checking it first. In the case of this CVE, the software uses the 'pickle' module to reconstruct data, which can inadvertently execute malicious commands hidden within that input.

How can an attacker trigger this vulnerability?

An attacker triggers this flaw by sending a specifically crafted 'pickled' data object to the FlightServer, for instance through the 'set_configs' action. The vulnerability is only reachable when the server is configured to accept connections. Internal processes that do not accept external data inputs or those that are not exposed to the network are not subject to this specific trigger path.

Is my instance of pyquokka at risk?

Halo Surface Signal indicates that while this is a critical vulnerability, pyquokka is typically deployed for internal data processing rather than as a public-facing service. Your risk is highest if the FlightServer has been misconfigured to listen on all network interfaces (0.0.0.0), which makes it accessible beyond a private, trusted environment.

How should I respond if I use pyquokka?

Begin by auditing your infrastructure to locate all active instances of the FlightServer component. Determine which instances are reachable over your network and assess their function. Once identified, assign ownership to your data engineering or platform teams to prioritize these instances for security updates or isolation, depending on their criticality to your operations.

References

github.com/marsupialtail/quokka/security/advisories/GHSA-f74j-gf…

Written by Nicholas Merritt

Nicholas Merritt is VP of Security Solutions at Halo Security. With more than 25 years across application security, vulnerability prioritization, and offensive security, he helps teams translate threat data into practical exposure validation and remediation focus. He authors Halo Threat Intelligence CVE advisories using Halo Surface Signal and H/A/L/O context to prioritize internet-facing risk.