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CVE-2026-85078— sanic chunked trailer request smuggling allows hidden second request execution

Quick assessment

Affected
sanic-org sanic
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.

Sanic 是一个开源的 Python Web 服务器/框架。在 25.12.0 版本中，Sanic 的核心 HTTP/1.1 分块编码（chunked）请求体处理逻辑存在问题：在读取终止的零长度分块（terminating zero chunk）之后，未完全消费掉分块末尾的 trailer 部分，随后便复用 keep-alive 连接缓冲区。一个远程未认证的攻击者可以将自己控制的字节放置在该 trailer 区域，导致 Sanic 在外部请求解析和路由过程中，将这些字节解析并路由为一个隐藏的第二个请求。这破坏了

CVSS 6.5 · Medium
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I. Basic Information for CVE-2026-85078

Vulnerability Information
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Vulnerability Title
sanic chunked trailer request smuggling allows hidden second request execution
Source: CVE Program / CVE List V5
Vulnerability Description
Sanic is an opensource python web server/framework. In version 25.12.0, Sanic's core HTTP/1.1 chunked-body handling does not fully consume the trailer-part after the terminating zero chunk before reusing the keep-alive connection buffer. A remote unauthenticated client can place attacker-controlled bytes in that trailer region, causing Sanic to parse and route them as a hidden second request after the outer request. This breaks HTTP request-boundary integrity and can provide a request-smuggling primitive when Sanic is deployed behind intermediaries. This issue is fixed in version 25.12.1.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L
Source: CVE Program / CVE List V5
Vulnerability Type
HTTP请求的解释不一致性(HTTP请求私运)
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
sanic-org sanic < 24.12.1 -

II. Public POCs for CVE-2026-85078

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III. Intelligence Information for CVE-2026-85078

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Patches & Fixes for CVE-2026-85078 (4)

Vendor Advisories for CVE-2026-85078 (1)

Vendor Pages for CVE-2026-85078 (2)

IV. Related Vulnerabilities

Same product: sanic
Same vendor: sanic-org
Same weakness: CWE-444

V. Comments for CVE-2026-85078

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