What’s Vulnerable › Vulnerabilities

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

• Severity: high (CVSS 8.2 v4.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-09-17 · updated 2026-09-24
• Weakness: CWE-674

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

• elixir-protobuf protobuf: from 0.8.0, < 0.16.1

References

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

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