Goal Reached Thanks to every supporter — we hit 100%!

Goal: 1000 CNY · Raised: 1336 CNY

100%
Buy Us a Coffee

CVE-2026-77528— Autobahn Python permessage-deflate bypasses maxMessagePayloadSize after inflation

Quick assessment

Affected
crossbario autobahn-python
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Autobahn Python 是一个支持 Twisted 和 asyncio 的 WebSocket 和 WAMP 的 Python 实现。在 26.7.1 版本之前，接受 permessage-deflate（每消息压缩）并依赖 的 WebSocket 端点，仅对压缩后的帧长度执行该限制，但未在解压缩后重新检查解压缩后的消息大小。一个远程未认证客户端可以发送一个低于配置的网络数据大小限制的合法压缩帧，该帧在解压缩后会超出应用程序的消息大小限制，从而导致超大数据被分配、拼接、验证并传递给应用程序回调。这可能造成资

CVSS 5.3 · Medium EPSS 0.40% · P34

Possible ATT&CK Techniques 1 AI

T1298

Affected Version Matrix 1

VendorProduct Version RangeStatus
crossbario autobahn-python < 26.7.1 affected
Get alerts for future matching vulnerabilities Log in to subscribe

I. Basic Information for CVE-2026-77528

Vulnerability Information
Have questions about the vulnerability? See if Shenlong's analysis helps!
View Shenlong Deep Dive ↗

Although we use advanced large model technology, its output may still contain inaccurate or outdated information.Shenlong tries to ensure data accuracy, but please verify and judge based on the actual situation.

Vulnerability Title
Autobahn Python permessage-deflate bypasses maxMessagePayloadSize after inflation
Source: CVE Program / CVE List V5
Vulnerability Description
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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Source: CVE Program / CVE List V5
Vulnerability Type
对高度压缩数据的处理不恰当(数据放大攻击)
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
crossbario autobahn-python < 26.7.1 -

II. Public POCs for CVE-2026-77528

# POC Description Source Link Shenlong Link
AI-Generated POC Premium

No public POC found.

Login to generate AI POC

III. Intelligence Information for CVE-2026-77528

请登录查看更多情报信息。

Patches & Fixes for CVE-2026-77528 (2)

Other References for CVE-2026-77528 (2)

IV. Related Vulnerabilities

Same weakness: CWE-409

V. Comments for CVE-2026-77528

No comments yet

Leave a comment