CVE-2026-121620 (CVSS 6.5)

Description

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.

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CVSS v3.1 Score

6.5

MEDIUM

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:L

EPSS — Exploit Prediction

0.0022

Probability of exploitation

0.13%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-345 CWE-345

References

Other References

https://github.com/coopcycle/coopcycle-web/blob/v6.19.1/config/packages/security.yaml#L328-L330 https://github.com/coopcycle/coopcycle-web/blob/v6.19.1/src/Integration/Zelty/ZeltyCatalogProcessor.php#L51-L57 https://github.com/coopcycle/coopcycle-web/commit/9b499950d433ca8ba894996d6b17f49885ca9485 https://github.com/coopcycle/coopcycle-web/releases/tag/v6.20.0 https://www.vulncheck.com/advisories/coopcycle-coopcycle-web-5.6.0-before-6.20.0-missing-zelty-webhook-signature-verification

Frequently Asked Questions

What is CVE-2026-121620? +

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. It has a CVSS v3.1 base score of 6.5 (MEDIUM).

How severe is CVE-2026-121620? +

CVE-2026-121620 has a CVSS v3.1 score of 6.5 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0022, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-121620? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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