CVE-2026-59729Public exploitNetwork attack vectorHinoki check available

XSS via unescaped spread attribute names

Published Jul 27, 2026 · Updated Jul 27, 2026

Cross-site scripting in Astro before 7.0.6 allows remote attackers to inject script through untrusted spread-property names. The renderHTMLElement loop in packages/astro/src/runtime/server/render/dom.ts interpolates each attribute name into server-rendered markup without validation while escaping only its value. Exploitation requires an SSR runtime that defines global HTMLElement, a native HTMLElement-subclass component receiving attacker-controlled keys, and a user who loads the output.

CVSS severity5.1
Medium
EPSS probability0.32%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Cross-site scripting in Astro before 7.0.6 allows remote attackers to inject script through untrusted spread-property names. The renderHTMLElement loop in packages/astro/src/runtime/server/render/dom.ts interpolates each attribute name into server-rendered markup without validation while escaping only its value. Exploitation requires an SSR runtime that defines global HTMLElement, a native HTMLElement-subclass component receiving attacker-controlled keys, and a user who loads the output.

The record

CVE
CVE-2026-59729
Published
Jul 27, 2026
Updated
Jul 27, 2026
Vendor
Astro Technology Company
Product
Astro
Classifications
CWE-79, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 27, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 27, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 7.0.6

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Astro Technology Company · Astroversion=< 7.0.6

Published CVSS scores

5.1GitHubCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1203Exploitation for Client Execution

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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