CVE-2026-64670: XSS (CVSS 9.3)

Description

Waline is a comment system with backend support. In versions 3.15.2 and prior, @waline/client renders the comment editor's live preview with marked and no sanitizer (utils/markdown.ts), and the preview is injected with v-html. When a comment is edited, the editor is seeded with the comment's raw, un-sanitized body (orig). Only administrators and the comment owner can edit. So an administrator who clicks Edit on an attacker's comment renders that attacker's raw HTML in their own session: an unauthenticated commenter achieves privilege-escalation stored XSS against a moderator with a single Edit click. At time of publication, there are no publicly available patches.

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CVSS v3.1 Score

9.3

CRITICAL

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

EPSS — Exploit Prediction

0.0036

Probability of exploitation

0.30%

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-79 Cross-site Scripting (XSS)

CWE-116 CWE-116

References

Other References

https://github.com/walinejs/waline/security/advisories/GHSA-crj3-q72p-ggqm https://github.com/walinejs/waline/security/advisories/GHSA-crj3-q72p-ggqm

Frequently Asked Questions

What is CVE-2026-64670? +

Waline is a comment system with backend support. In versions 3.15.2 and prior, @waline/client renders the comment editor's live preview with marked and no sanitizer (utils/markdown.ts), and the preview is injected with v-html. When a comment is edited, the editor is seeded with the comment's raw, un-sanitized body (orig). Only administrators and the comment owner can edit. So an administrator who clicks Edit on an attacker's comment renders that attacker's raw HTML in their own session: an unauthenticated commenter achieves privilege-escalation stored XSS against a moderator with a single Edit click. At time of publication, there are no publicly available patches. It has a CVSS v3.1 base score of 9.3 (CRITICAL).

How severe is CVE-2026-64670? +

CVE-2026-64670 has a CVSS v3.1 score of 9.3 out of 10, rated CRITICAL. This is a critical vulnerability that should be patched immediately. The EPSS score is 0.0036, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-64670? +

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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