Vulnerability · Published Sep 17, 2026 · Assigned by GitHub_M

CVE-2026-54451Elixir protobuf: Unbounded recursion depth in embedded-message decoding

High 8.2

In plain English

A high-severity security flaw in protobuf from elixir-protobuf. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 45% of all known vulnerabilities).

Severity (CVSS 4.0)8.2High

Exploit odds (30 days)0.5%top 55.4% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official description

Elixir protobuf is a pure Elixir implementation of Google Protobuf. From 0.8.0 until 0.16.1, services that decode attacker-controlled protobuf bytes with Protobuf.Decoder can be taken offline when the schema contains a self-referential or cyclic message type. In lib/protobuf/decoder.ex, Protobuf.Decoder.value_for_field/3 handles an embedded?: true field by recursively entering the decode / build_message / handle_value / value_for_field call chain without enforcing a nesting-depth limit. Deeply nested embedded fields retain non-tail recursive frames, allowing a comparatively small request to consume substantial CPU and memory, pin a BEAM scheduler, and exhaust the node. This issue is fixed in version 0.16.1.

Affected products (as reported)

Vendor	Product	Versions
elixir-protobuf	protobuf	>= 0.8.0, < 0.16.1

Weakness: CWE-674 · Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

References

https://github.com/elixir-protobuf/protobuf/security/advisories/GHSA-rv48-qqj5-crxg x_refsource_CONFIRM
https://github.com/elixir-protobuf/protobuf/commit/352d1769a0ef575a8d18c3f9620609efdb73e2bc x_refsource_MISC
https://github.com/elixir-protobuf/protobuf/commit/b8efa97790eece3d2d0e8e7c31a45ed409fe5338 x_refsource_MISC
https://github.com/elixir-protobuf/protobuf/releases/tag/v0.16.1 x_refsource_MISC