CVE-2026-55612

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    CVE-2026-55612

    Published: 30 Oct 2026Last Modified: 4 Nov 2026

    Summary: uhttpd vulnerable to HTTP request smuggling via invalid chunk-length state reset

    Details: 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.

    References: https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/55xxx/CVE-2026-55612.json, https://github.com/openwrt/uhttpd/security/advisories/GHSA-p55c-rmhc-qfm5, https://nvd.nist.gov/vuln/detail/CVE-2026-55612, https://github.com/openwrt/uhttpd/commit/34460b8211d676ef1b9f40d6b775c5e112933690, https://github.com/openwrt/uhttpd/commit/b78f518478794e16ba3568fc1258e40bf3e8eb3b

    Affected packages

    Package

    Name:

    Purl:

    Affected ranges

    Type: GIT

    Events:

    Introduced- b7c85a2819b3869279a669d5681f574824589c6c
    Fixed -b78f518478794e16ba3568fc1258e40bf3e8eb3b

    Affected versions

    Common Vulnerability Scoring System

    Attack Vector
    Network
    Adjacent
    Local
    Physical
    Privileges Required
    None
    Low
    High
    User Interaction
    None
    Required
    Scope
    Unchanged
    Changed
    Confidentiality
    None
    Low
    High
    Integrity
    None
    Low
    High
    Availability
    None
    Low
    High
    CVE-2026-55612 | CVE-DB