CVE-2026-59729

MEDIUM
MEDIUM Priority: 0.02 BB Relevance: 60/100
Published: 2026-07-27 Modified: 2026-10-24 First seen: 2026-10-29 Status: active

Attack Surface

Network Low Complexity No Auth

CVSS Vector Breakdown

AV: Network
AC: Low
PR: None
UI: Active
S: X
AT: None
VC: None
VI: None
VA: None

Description

Astro is a web framework for content-driven websites. Versions prior to 7.0.6 are vulnerable to XSS through unescaped spread attribute names in renderHTMLElement. The fix for CVE-2026-54298 (GHSA-jrpj-wcv7-9fh9) added an INVALID_ATTR_NAME_CHAR guard to addAttribute() so that spread-prop attribute names containing "' >/= or whitespace are dropped. A second attribute-rendering path, renderHTMLElement() in packages/astro/src/runtime/server/render/dom.ts, has its own inline attribute loop that does not go through addAttribute() and was not updated. It interpolates the attribute name unescaped and only escapes the value, so untrusted prop keys spread onto a native-HTMLElement-subclass component can still break out of the attribute context. This issue has been fixed in version 7.0.6.

Weakness Classification (1)

Bug Bounty Relevance

60 / 100
✓ Network accessible
✓ No authentication
✓ Low complexity

CVSS Score

5.1 / 10.0 v4.0
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS — Exploitation Probability

0.47%
Raw Score 0.004730
Percentile 40.9%
Date 2026-10-29

EPSS Trend

2026-10-29
0.00473
2026-10-28
0.00473

Intelligence Sources

nvd ref →