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CVE-2026-77528

Autobahn Python permessage-deflate bypasses maxMessagePayloadSize after inflation PUBLISHED

Description (CNA)

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 (CNA)

Vendor / productVersions
crossbario / autobahn-pythonaffected < 26.7.1

CWE

CWE-409, CWE-770

References

ADP enrichment

CISA-ADP

No English description supplied.

No references supplied.