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

Goal: 1000 CNY · Raised: 1359 CNY

100%
Buy Us a Coffee

CVE-2026-16728— undici vulnerable to downstream response desynchronization via retry interceptor

Quick assessment

Affected
undici undici
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.

undici undici是undici组织的一个HTTP客户端库。 undici 6.28.0之前版本、7.0.0版本至7.29.0之前版本和8.0.0版本至8.9.0之前版本存在输入验证错误漏洞，该漏洞源于retry interceptor在重试或恢复部分响应时，传递的响应体长度与Content-Length头不匹配，可能导致下游响应去同步、连接挂起或响应损坏。

CVSS 4.8 · Medium EPSS 0.29% · P21

Affected Version Matrix 6

VendorProduct Version RangeStatus
undici undici < 6.28.0 affected
6.28.0 unaffected
7.0.0< 7.29.0 affected
7.29.0 unaffected
8.0.0< 8.9.0 affected
8.9.0 unaffected
Get alerts for future matching vulnerabilities Log in to subscribe

I. Basic Information for CVE-2026-16728

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Although we use advanced large model technology, its output may still contain inaccurate or outdated information.Shenlong tries to ensure data accuracy, but please verify and judge based on the actual situation.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
undici vulnerable to downstream response desynchronization via retry interceptor
Source: CVE Program / CVE List V5
Vulnerability Description
undici's retry interceptor can deliver a response whose body length does not match the Content-Length header exposed to the application after a retry or resume of a partial response. In undici before 6.28.0, from 7.0.0 up to before 7.29.0, and from 8.0.0 up to before 8.9.0, a malicious or faulty upstream can return a partial response with a mismatched framing header, close the socket early, and have the retry interceptor assemble a body of a different length while the original Content-Length stays attached. Applications that use the retry interceptor and forward upstream headers and bodies downstream, such as proxies or gateways, may then emit an invalid HTTP response with a stale Content-Length, leading to downstream response desynchronization, connection hangs, or response corruption. Exploitation requires the retry interceptor enabled, an upstream returning a mismatched partial response, and a downstream forwarder that does not remove or recalculate Content-Length. The issue is fixed in undici 6.28.0, 7.29.0, and 8.9.0.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N
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
Vulnerability Title
undici 输入验证错误漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
undici undici是undici组织的一个HTTP客户端库。 undici 6.28.0之前版本、7.0.0版本至7.29.0之前版本和8.0.0版本至8.9.0之前版本存在输入验证错误漏洞，该漏洞源于retry interceptor在重试或恢复部分响应时，传递的响应体长度与Content-Length头不匹配，可能导致下游响应去同步、连接挂起或响应损坏。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
undici undici 0 ~ 6.28.0 -

II. Public POCs for CVE-2026-16728

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

No public POC found.

Login to generate AI POC

III. Intelligence Information for CVE-2026-16728

请登录查看更多情报信息。

Vendor Advisories for CVE-2026-16728 (1)

Same Patch Batch · undici · 2026-07-29 · 5 CVEs total

CVE-2026-13697 7.4 HIGH undici vulnerable to cross-user information disclosure and parse-time crash via degenerate
CVE-2026-14643 5.9 MEDIUM undici vulnerable to cross-user information disclosure via whitespace around equals in Cac
CVE-2026-16729 4.8 MEDIUM undici vulnerable to cookie attribute injection via unsanitized domain and unparsed setCoo
CVE-2026-15157 4.2 MEDIUM undici vulnerable to CRLF Injection via blob-like body 'type' property

IV. Related Vulnerabilities

Same product: undici
Same vendor: undici
Same weakness: CWE-444