CVE-2026-85061: MapLibre GL JS: XSS Sanitizer Bypass in DOM.sanitize() via Live NamedNodeMap Removal Skip

Should you act?

Critical and remotely reachable

No known exploitation yet, but it is network-reachable without credentials. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

• No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
• EPSS 0.5%, percentile 43: FIRST’s model estimates a 0.5% chance of exploitation activity in the next 30 days, higher than 43% of all scored CVEs (low). EPSS is a probability, not a verdict.
• Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
• Only applies if your dependency tree includes maplibre-gl (npm) <= 6.4.0, fixed in 6.4.1. Check your lockfile, including transitive dependencies.

What it is

MapLibre GL JS is an interactive vector tile map library for web browsers. Prior to 6.4.1, DOM.sanitize() in src/util/dom.ts iterates elem.attributes as a live NamedNodeMap while removeAttributes() removes attributes from the same collection, shifting indexes and skipping an adjacent dangerous attribute. An attacker who controls untrusted third-party style attribution strings or user-supplied custom attributions can supply consecutive dangerous attributes, causing an attribute such as onload or ontoggle to survive sanitization and execute when the attribution control inserts the content into innerHTML. A victim must render the affected map content for the script to execute. This issue is fixed in version 6.4.1.

From the GitHub advisory

Impact DOM.sanitize() in src/util/dom.ts iterated elem.attributes (a live NamedNodeMap) while calling elem.removeAttribute() in the same loop. Removing an attribute shifts subsequent attributes down by one index, causing the iterator to skip the adjacent attribute.

An attacker can provide an HTML payload with consecutive dangerous attributes (such as ). The first attribute is stripped while the second survives and executes upon insertion into innerHTML via the attribution control without requiring user interaction (zero-click XSS).

Applications rendering untrusted/third-party style attribution strings or user-supplied custom attributions are impacted.

Patches The issue has been resolved by creating a static snapshot of attributes using Array.from(elem.attributes) before iteration. Please upgrade to maplibre-gl version 6.4.1 (or latest).

Workarounds Sanitizing the attribute field of a source before passing it down to maplibre

Weakness type: CWE-79.

Product: maplibre-gl (npm) · Assigned by: GitHub_M · Published: 2026-09-03

Affected and fixed versions

Severity scores

• Attack vector: network (remotely reachable)
• Attack complexity: low
• Privileges required: none (no login)
• User interaction: none
• Scope: changed (can affect other components)

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

• CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
• CISA SSVC assessment: exploitation none, automatable yes, technical impact total.
• FIRST EPSS (model of 2026-10-21): 0.52% probability of exploitation activity in the next 30 days; percentile 43.

Timeline

• 2026-09-03 — CVE record published by GitHub_M
• 2026-09-04 — CVE record last updated
• 2026-09-08 — GitHub-reviewed advisory GHSA-jrc7-96c5-q579 published (critical)

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.

Vulnerability records

1. GitHub Advisory GHSA-jrc7-96c5-q579 github.com
2. CVE.org record CVE-2026-85061 cve.org
3. NVD entry CVE-2026-85061 nvd.nist.gov

Other references from the CVE record and advisory

1. github.com github.com
2. github.com github.com
3. github.com github.com
4. github.com github.com

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