Description
Buffa is a pure-Rust Protocol Buffers implementation with first-class protobuf editions support. Prior to 0.8.0, the decode_unknown_field function in buffa's protobuf decoder allocated heap memory in proportion to untrusted input (unknown fields in the serialized protobuf) without enforcing an allocation budget, affecting any message decoded from untrusted input using code generated with preserve_unknown_fields=true (the default); a small, well-formed payload of nested unknown fields inside a StartGroup could trigger roughly 22x memory amplification (for example a 64 MiB input forcing about 1.4 GB of heap allocation), and length-delimited unknown fields could be sized arbitrarily, so an unauthenticated attacker could crash a process through memory exhaustion because the top-level message size cap did not account for in-decode amplification. This issue is fixed in version 0.8.0.
Published: 2026-07-16
Score: 6.3 Medium
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
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History

Thu, 16 Jul 2026 16:30:00 +0000

Type Values Removed Values Added
Description Buffa is a pure-Rust Protocol Buffers implementation with first-class protobuf editions support. Prior to 0.8.0, the decode_unknown_field function in buffa's protobuf decoder allocated heap memory in proportion to untrusted input (unknown fields in the serialized protobuf) without enforcing an allocation budget, affecting any message decoded from untrusted input using code generated with preserve_unknown_fields=true (the default); a small, well-formed payload of nested unknown fields inside a StartGroup could trigger roughly 22x memory amplification (for example a 64 MiB input forcing about 1.4 GB of heap allocation), and length-delimited unknown fields could be sized arbitrarily, so an unauthenticated attacker could crash a process through memory exhaustion because the top-level message size cap did not account for in-decode amplification. This issue is fixed in version 0.8.0.
Title Buffa: Memory Exhaustion Denial of Service in decode_unknown_field via Unbounded Allocation
Weaknesses CWE-400
CWE-770
CWE-789
References
Metrics cvssV4_0

{'score': 6.3, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N'}

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-07-16T15:57:31.704Z

Reserved: 2026-06-16T21:48:43.124Z

Link: CVE-2026-55407

cve-icon Vulnrichment

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cve-icon NVD

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cve-icon Redhat

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cve-icon OpenCVE Enrichment

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Weaknesses
  • CWE-400

    Uncontrolled Resource Consumption

  • CWE-770

    Allocation of Resources Without Limits or Throttling

  • CWE-789

    Memory Allocation with Excessive Size Value