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.
Advisories
| Source | ID | Title |
|---|---|---|
Github GHSA |
GHSA-8xcm-r25x-g524 | undici vulnerable to downstream response desynchronization via retry interceptor |
Fixes
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
References
History
Thu, 30 Jul 2026 16:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Metrics |
ssvc
|
Wed, 29 Jul 2026 23:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| First Time appeared |
Undici
Undici undici |
|
| Vendors & Products |
Undici
Undici undici |
Wed, 29 Jul 2026 21:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| 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. | |
| Title | undici vulnerable to downstream response desynchronization via retry interceptor | |
| Weaknesses | CWE-444 | |
| References |
| |
| Metrics |
cvssV3_1
|
Projects
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Status: PUBLISHED
Assigner: openjs
Published:
Updated: 2026-07-30T15:18:18.440Z
Reserved: 2026-07-23T04:21:23.161Z
Link: CVE-2026-16728
Updated: 2026-07-30T14:20:10.317Z
No data.
No data.
OpenCVE Enrichment
Updated: 2026-08-02T07:45:03Z
Weaknesses
Github GHSA