CVE-2026-103266: Auth Bypass (CVSS 7.1)

Description

Ghost versions 5.2.0 through versions prior to 6.62.0 allow a remote attacker, without authentication, to abuse the Stripe Checkout flow to attach a paid subscription to an existing member, modify that member's name, and inject content into newsletters sent to the member. Depending on the recipient's email client, the injected content may be rendered, resulting in HTML injection or cross-site scripting (XSS).

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CVSS v3.1 Score

7.1

HIGH

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

EPSS — Exploit Prediction

0.0030

Probability of exploitation

0.21%

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-863 Incorrect Authorization

References

Other References

https://github.com/TryGhost/Ghost/security/advisories/GHSA-qppx-rw6v-xjqf https://www.vulncheck.com/advisories/ghost-5.2.0-before-6.62.0-unauthenticated-stripe-checkout-account-modification

Frequently Asked Questions

What is CVE-2026-103266? +

Ghost versions 5.2.0 through versions prior to 6.62.0 allow a remote attacker, without authentication, to abuse the Stripe Checkout flow to attach a paid subscription to an existing member, modify that member's name, and inject content into newsletters sent to the member. Depending on the recipient's email client, the injected content may be rendered, resulting in HTML injection or cross-site scripting (XSS). It has a CVSS v3.1 base score of 7.1 (HIGH).

How severe is CVE-2026-103266? +

CVE-2026-103266 has a CVSS v3.1 score of 7.1 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0030, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-103266? +

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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