CVE
Astro cross-site scripting in dynamic element name rendering
- Exploited
- No known exploitation
- Fix
- Fixed in 7.4.5
- Who is exposed
- Not reported
Do first: Upgrade to a fixed version: 7.4.5.
- Last modified
- Whether it needs action now or is a reference record, by fixed rules, with why. Last checked is when cve.now last re-read it.What do these mean? →
- Reference
- Last checked
- FIRST's estimate of the chance attackers exploit it in the next 30 days, updated daily.What do these mean? →
- 0.32% · 24th percentile
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 9/100 · provisional
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
Astro, a web framework for content-driven websites, has a cross-site scripting flaw in how it renders dynamic element names. An attacker can reach it remotely, without logging in, but a user must take an action, and the attack only works when an application uses untrusted request or stored data as all or part of an element name.
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
Read the original description
Astro is a web framework for content-driven websites. Prior to 7.4.5, Astro rendered a string used as a dynamic element name as raw HTML after applying an incomplete character filter. A / in the string could make an HTML parser treat the remainder as attributes, allowing untrusted element-name input to inject event-handler markup. The .astro dynamic-tag renderer, JSX renderer, and MDX renderer were affected, and exploitation required an application to use request-controlled or stored untrusted data as all or part of an element name. This issue is fixed in version 7.4.5.
cve.now Index
- Exploitation?/40Unknown. No CISA SSVC exploitation rating yet
- Exposure7/25Reachable over the network without a login · Unknown: No advisory context yet
- Reach?/20Unknown. No tracked technology or package matched
- Severity2.3/10CVSS 2.3
- No patch0/5No signal
What would change the score
- Would score about 64 if added to CISA KEV
- Would score about 59 if CISA's SSVC rates exploitation active
- Would score about 24 if advisories confirm default setups are exposed
What to do
Upgrade to a fixed version: 7.4.5.
Check your systems with an agent
Paste this into a coding or ops agent. It checks your systems read-only and reports a table per asset.
Check whether my systems are affected by CVE-2026-126361 (Astro: XSS via attribute injection in dynamic tag names), using the cve.now data below.
Rules: work read-only. Do not run exploit code, proof-of-concept scripts or scanners that send attack payloads, and do not change any configuration, package, image or deployment. Report findings only.
What cve.now has for CVE-2026-126361 (entry last updated 2026-11-12):
Affected:
- withastro astro: fixed in 7.4.5
Fixed versions: 7.4.5.
Setup: unknown whether the bug needs a non-default feature or setting. Check the advisory.
CISA KEV: CVE-2026-126361 is not listed as of cve.now's last read.
This KEV status is for CVE-2026-126361 only. If you also check another CVE, look up its own KEV status; never assume it from this one.
How to check:
- Installed software: check what is actually running, not what a repo declares. Read the version from each host, container image and Kubernetes node (the binary's version output, the OS package database, image layers), and check whether the conditions above hold there. Distribution packages may carry a backported fix under an older version number; confirm against the distribution's own advisory.
Verify against the linked advisories before concluding, and cite the date you read each one:
- https://github.com/withastro/astro/security/advisories/GHSA-mh32-jxcr-mh9f
- https://github.com/withastro/astro/pull/18520
- https://github.com/withastro/astro/commit/e023abac912d7cb6af2b9fb5107ef5dabc667096
- https://github.com/withastro/astro/releases/tag/astro@7.4.5
Do not conclude an asset is unaffected unless you checked it and the evidence covers both its version and the conditions above. If you could not check something, mark it unknown and say what is missing.
Report a table with one row per asset and these columns: Asset | Version or build | Status (affected, fixed, not applicable, unknown) | Compensating controls | Exposure (internet-facing, internal, none) | Evidence | Next action.
Entry: https://cve.now/CVE-2026-126361
For follow-up questions, use the cve.now MCP server at https://mcp.cve.now/mcp (no authentication), for example execute with name cve.get and arguments {"id": "CVE-2026-126361"}.Timeline
- CVE published
- First seen by cve.now
Affected versions
- withastro astro
fixed in 7.4.5
Evidence 6
Vendor advisory · 1
Establishes: Affected and fixed versions.
- Advisory
CVE record · 2
Establishes: The identifier and description.
- Record
- Record
Other links · 3
- Repository
- Repository
- Repository
Corrections
None so far.
Something wrong on this page? Report an error. Every fix is listed here.
Questions about CVE-2026-126361
Is CVE-2026-126361 being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data
Which versions are affected by CVE-2026-126361?
astro: before 7.4.5.Source: cve.now feed data
How do I fix CVE-2026-126361?
Upgrade to a fixed version: 7.4.5.Source: cve.now feed data