CVE-2026-104635

What it is

Uncontrolled Recursion vulnerability in Protobuf.JSON.Decode in elixir-protobuf protobuf allows an unauthenticated remote attacker to crash the decoding process via a deeply nested JSON document. Any application that decodes attacker-supplied JSON with Protobuf.JSON.decode/3, Protobuf.JSON.decode!/3, or Protobuf.JSON.from_decoded/3 into a schema that contains a self-referential or cyclic message type is affected. In lib/protobuf/json/decode.ex, the embedded-message clause of decode_singular/3 recurses into internal_from_json_data/3 once per nesting level without incrementing or checking the decoder's depth counter. The depth guard increase_depth_and_maybe_throw/1 covers only the Google.Protobuf.ListValue and Google.Protobuf.Struct clauses, so the recursion_limit option has no effect on user-defined message types. Each nesting level allocates a stack frame and heap objects, and a sufficiently deep document exhausts the memory of the decoding process. Confidentiality and integrity are not affected. This issue affects protobuf: from 0.8.0 before 0.17.1.

At a glance

Exploitability

Can be exploited over the network without logging in. High risk of service disruption.

Exploit odds

0.5% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2026-10-09 09:17 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-10-15 16:17 UTC Last updatedMost recent change to the record

Details

Published

2026-10-09 09:17 UTC

Last modified

2026-10-15 16:17 UTC

Exploit probability

0.5% · EPSS, next 30 days

Weakness

CWE-674

Record status

Deferred

Attack profile CVSS 4.0 · 8.2

Attack vector

Network

Complexity

Low

Attack requirements

Present

Privileges needed

None

User interaction

None

Confidentiality

None

Integrity

None

Availability

High