# CVE-2026-121620: CoopCycle coopcycle-web 5.6.0 before 6.20.0 Missing Zelty Webhook Signature Verification

Status: published. Published: 2026-11-04. Updated: 2026-11-04.

CoopCycle coopcycle-web 5.6.0 before 6.20.0 contains a missing authentication vulnerability that allows unauthenticated attackers to forge Zelty webhook events because the x-zelty-hmac-sha256 HMAC signature is never verified. Attackers can POST forged dish, menu, option and order-status events to /api/zelty/webhook/* endpoints to toggle restaurant products and alter order preparation states.

## Remediation

- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: CNA: VulnCheck) — https://github.com/coopcycle/coopcycle-web/commit/9b499950d433ca8ba894996d6b17f49885ca9485

## Affected products and versions

- CoopCycle / coopcycle-web (coopcycle/coopcycle-web): ≥ 5.6.0; < 6.20.0 (affected, semver). Source: CNA: VulnCheck

## Severity and prioritization

- CVSS 4.0: 8.3 (high); CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:H/VA:L/SC:N/SI:N/SA:N; source: CNA: VulnCheck

- CVSS 3.1: 6.5 (medium); CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:L; source: CNA: VulnCheck

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: Not available

- Weaknesses: CWE-345

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://github.com/coopcycle/coopcycle-web/commit/9b499950d433ca8ba894996d6b17f49885ca9485 (CNA: VulnCheck; patch)

- https://github.com/coopcycle/coopcycle-web/releases/tag/v6.20.0 (CNA: VulnCheck; release-notes)

- https://github.com/coopcycle/coopcycle-web/blob/v6.19.1/config/packages/security.yaml#L328-L330 (CNA: VulnCheck; technical-description)

- https://github.com/coopcycle/coopcycle-web/blob/v6.19.1/src/Integration/Zelty/ZeltyCatalogProcessor.php#L51-L57 (CNA: VulnCheck; technical-description)

- https://www.vulncheck.com/advisories/coopcycle-coopcycle-web-5.6.0-before-6.20.0-missing-zelty-webhook-signature-verification (CNA: VulnCheck; third-party-advisory)

## Provenance

- CNA: VulnCheck: https://www.cve.org/CVERecord?id=CVE-2026-121620; retrieved 2026-11-04; source updated 2026-11-04

Revision: 3c2f2a85c245348d48a5d4b0d73eb3ca520e122d0760b845ec95d701a8b21487

Canonical: https://y2.dev/cve/CVE-2026-121620

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