CVE-2026-0994

A denial-of-service (DoS) vulnerability exists in google.protobuf.json_format.ParseDict() in Python, where the max_recursion_depth limit can be bypassed when parsing nested google.protobuf.Any messages. Due to missing recursion depth accounting inside the internal Any-handling logic, an attacker can supply deeply nested Any structures that bypass the intended recursion limit, eventually exhausting Python’s recursion stack and causing a RecursionError.

What this means for your business

It affects Google Protobuf. It matters if your company, or a supplier that handles your data, runs it.
An attacker can use it remotely, over a network, without a login, and without anyone at your company clicking anything.
FIRST's prediction model gives it a 0.7% chance of attack attempts being seen in the next 30 days, ranking above 50% of all known flaws.

What to do

1Check whether your company or your suppliers run Google Protobuf, and which version. The affected versions are listed further down this page.
2If you do, apply the vendor's fix. A patch or vendor advisory has been published.

Not sure if your company is exposed?

Fastnexa’s certified penetration testers can check whether attackers could use this flaw, or others like it, against your websites, apps and network. The full test is free for our first 10 founding clients until 31 December 2026.

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Scoring

CVSS: 7.5 (v3.1)
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS v4: 8.2
Weakness: CWE-674
Assigned by: cve-coordination@google.com

Dates

Published: 2026-01-23
Last modified: 2026-09-01
Sources: NVD

Affected products

Google Protobuf- 33.4

As listed in the NVD configuration data. Not a statement about your estate.