# CVE-2026-55613: uhttpd: HTTP request smuggling via ubus POST body parse-error desync

Status: published. Published: 2026-10-30. Updated: 2026-11-05.

uhttpd is a small HTTP server. In unpatched repository snapshots, `uh_ubus_data_send()` in `ubus.c` can desynchronize HTTP request boundaries when a `POST /ubus` JSON body arrives in multiple TCP segments. An initial segment completing a JSON object sets `du->jsobj`; a later segment takes the existing-object parse-error path and returns zero bytes consumed. The caller neither drains the remaining declared `Content-Length` nor sets `connection_close`. An HTTP request embedded in the unread body suffix is consequently processed as a new request on the same keep-alive connection. The reported reproducer returned a JSON-RPC parse error followed by a second HTTP response. This application-layer body-handler flaw is distinct from Transfer-Encoding header case handling and chunk-length state reset, and affects deployments enabling ubus, including the default OpenWrt configuration and potential proxy/CDN deployments. Repository patches 7b1bec45826bd78c8afc993435bdc0f1df2fe399 and b2285de129b9adc8b12f84f9a27c16c21f2b57a5 address this issue.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- openwrt / uhttpd: < 7b1bec45826bd78c8afc993435bdc0f1df2fe399 (affected). Source: CNA: GitHub_M

## Severity and prioritization

- CVSS 4.0: 6.9 (medium); CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N; source: CNA: GitHub_M

- CVSS 4.0: 6.9 (medium); CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X; source: NVD: security-advisories@github.com

- CISA KEV: No listing in collected sources

- EPSS: 0.40% as of 2026-11-04; percentile 33.89%

- SSVC: exploitation poc; automatable yes; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-444

## Exploit evidence

- exploit: https://github.com/openwrt/uhttpd/security/advisories/GHSA-wgwp-64hh-f52p (ADP: CISA-ADP)

## References

- https://github.com/openwrt/uhttpd/security/advisories/GHSA-wgwp-64hh-f52p (CNA: GitHub_M; x_refsource_CONFIRM)

- https://github.com/openwrt/uhttpd/commit/7b1bec45826bd78c8afc993435bdc0f1df2fe399 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/openwrt/uhttpd/commit/b2285de129b9adc8b12f84f9a27c16c21f2b57a5 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/openwrt/uhttpd/security/advisories/GHSA-wgwp-64hh-f52p (ADP: CISA-ADP; exploit)

- https://github.com/openwrt/uhttpd/commit/7b1bec45826bd78c8afc993435bdc0f1df2fe399 (security-advisories@github.com)

- https://github.com/openwrt/uhttpd/commit/b2285de129b9adc8b12f84f9a27c16c21f2b57a5 (security-advisories@github.com)

- https://github.com/openwrt/uhttpd/security/advisories/GHSA-wgwp-64hh-f52p (security-advisories@github.com)

## Provenance

- CNA: GitHub_M: https://www.cve.org/CVERecord?id=CVE-2026-55613; retrieved 2026-11-05; source updated 2026-11-05

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-55613; retrieved 2026-11-03; source updated 2026-11-02

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-55613; retrieved 2026-11-05; source updated Not reported

Revision: f7cce7f15eea6618c4d073d741f1a480617cb55a0356ac55c7ba6f668415d21a

Canonical: https://y2.dev/cve/CVE-2026-55613

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