How severe is CVE-2026-55795?

No CVSS score has been assigned to CVE-2026-55795 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-55795?

CVE-2026-55795 affects the following packages: craftcms/commerce (Packagist), craftcms/commerce (Packagist). Ecosystems affected: Packagist.

How do I fix CVE-2026-55795?

Update craftcms/commerce to 5.6.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-55795 is resolved across your whole dependency graph.

How do I detect CVE-2026-55795 in my Packagist dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for craftcms/commerce, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2026-55795 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Is CVE-2026-55795 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-55795 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-55795?

CVE-2026-55795 has an EPSS (Exploit Prediction Scoring System) score of 0.5%, placing it in the 43th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-55795?

CVE-2026-55795 is classified as CWE-307 (CWE-307). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2026-55795 published, and has it been updated?

CVE-2026-55795 was published on September 14, 2026 and was last updated on October 21, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐘 Packagist

Not in CISA KEV

CVE-2026-55795 — commerce

Fix: craftcms/commerce@a7d365c

CVE-2026-55795 is a CWE-307 vulnerability in craftcms/commerce. A fix is available for craftcms/commerce — see the affected versions and patch details below.

Craft Commerce: Coupon Code Brute-Force via Rate Limit Bypass

Also known asGHSA-h5gm-x9wr-vhcm

Published

Sep 14, 2026

Updated

Oct 21, 2026

Affected

2 pkgs

Patched

2 / 2

Exploits

None indexed

Exploitation data as of Oct 23, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-55795.

EPSS Exploitation Probability

via FIRST.org ↗

0.5%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs43th percentile — riskier than 43% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

2 pkgs affected

🐘craftcms/commerce🐘craftcms/commerce

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.

Description

Summary

The CartController defines a RateLimiter behavior that is only activated when the 'number' POST/GET parameter is explicitly provided.

Details

When an attacker submits coupon codes against the session-based cart (without passing a 'number' parameter), no rate limiting is applied. This allows unlimited attempts to guess coupon codes.

Vulnerable Code <img width="864" height="90" alt="resim" src="https://github.com/user-attachments/assets/a5197f10-f1fd-4331-93f9-9479d0ceebba" />

PoC

Complete instructions, including specific configuration details, to reproduce the vulnerability.

Impact

An attacker can enumerate all coupon codes through automated requests.

Remediation Apply rate limiting unconditionally on actionUpdateCart regardless of whether 'number' is present.

Affected Packages

2 total 2 fixed

Ecosystem	Package	Vulnerable range	Fix
🐘Packagist	`craftcms/commerce`	≥ 5.0.0&&< 5.6.5	5.6.5`composer require craftcms/commerce:^5.6.5`
🐘Packagist	`craftcms/commerce`	≥ 4.0.0&&< 4.11.2	4.11.2`composer require craftcms/commerce:^4.11.2`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for craftcms/commerce, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update craftcms/commerce to 5.6.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-55795 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Frequently Asked Questions

### Summary The CartController defines a RateLimiter behavior that is only activated when the 'number' POST/GET parameter is explicitly provided. ### Details When an attacker submits coupon codes against the session-based cart (without passing a 'number' parameter), no rate limiting is applied. This allows unlimited attempts to guess coupon codes. **Vulnerable Code** <img width="864" height="90" alt="resim" src="https://github.com/user-attachments/assets/a5197f10-f1fd-4331-93f9-9479d0ceebba" /> <img width="881" height="272" alt="resim" src="https://github.com/user-attachments/assets/d9db9

O3 Security · Impact-Aware SCA

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