CVE-2026-55612

CVSS 3.7 (low) · published 2026-10-30

uhttpd is a small HTTP server. In unpatched repository snapshots, `client_poll_post_data()` in `client.c` consumes an invalid chunk-length line, such as a size exceeding INT_MAX, then clears `r->content_length` and `r->transfer_chunked` without draining the remaining body or setting `request.connection_close`. The completion check treats the chunked POST as finished and the keep-alive parser returns to `CLIENT_STATE_INIT`. Attacker-controlled body bytes aligned as a complete HTTP request are then parsed and processed as another request on the same connection, causing HTTP request smuggling and request-boundary desynchronization. Commits b78f518478794e16ba3568fc1258e40bf3e8eb3b and 34460b8211d676ef1b9f40d6b775c5e112933690 patch the issue.

Weakness: CWE-444

Source: NVD CVE-2026-55612

References

• https://github.com/openwrt/uhttpd/commit/34460b8211d676ef1b9f40d6b775c5e112933690
• https://github.com/openwrt/uhttpd/commit/b78f518478794e16ba3568fc1258e40bf3e8eb3b
• https://github.com/openwrt/uhttpd/security/advisories/GHSA-p55c-rmhc-qfm5

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