CVE-2026-77528

Summary

Autobahn Python is a WebSocket and WAMP implementation for Python that supports Twisted and asyncio. Prior to 26.7.1, WebSocket endpoints that accept permessage-deflate and rely on maxMessagePayloadSize enforce that limit against the compressed frame length before inflation but do not recheck the decompressed message size before delivery. A remote unauthenticated client can send a valid compressed frame below the configured wire-size limit that expands beyond the application message limit, causing oversized data to be allocated, joined, validated, and passed to application callbacks. This can create resource-exhaustion pressure, but the advisory does not establish confidentiality or integrity impact. This issue is fixed in version 26.7.1.

Affected Software

VendorProductVersion RangeStatus
crossbarioautobahn-python< 26.7.1affected

Weaknesses

  • CWE-409: CWE-409: Improper Handling of Highly Compressed Data (Data Amplification)
  • CWE-770: CWE-770: Allocation of Resources Without Limits or Throttling

References