Vulnerability Snapshot
CVE-2025-15646 is rated CRITICAL — exploitation is trivial or already observed in the wild and impact is severe. Patch immediately, not on the next maintenance window.
Executive Summary
HTML::Gumbo versions before 0.19 for Perl disclose heap memory via type confusion.
Support for the element was added to libgumbo 0.10.0 in 2015, but the walk_tree function in lib/HTML/Gumbo.xs was not updated to support it. The element was treated as a text-node, where strlen() over-reads the heap block that the pointer addresses.
Any caller that runs parse() with the default format => 'string', or with format => 'tree', on input containing a element serializes the over-read bytes into the returned result, disclosing bounded heap contents. format => 'callback' reaches a croak on the unhandled node type and is unaffected.
Why It Matters
CVE-2025-15646 is rated CRITICAL severity, requiring immediate attention from security teams.
CVSS Base Score: 9.8/10
🛡️What Defenders Should Check
Use Vulnios to continuously monitor your exposure to CVE-2025-15646 and similar vulnerabilities.
References & Sources
How Vulnios Detects This
Vulnios scans for this vulnerability using Trivy and Grype for SBOM-based CVE matching and Vulnios CVE feed continuous monitoring against your asset inventory. Run a scan against your environment to see whether you are exposed; findings are linked back to the original CVE record so triage starts with the patch path already known.
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Sources
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Frequently Asked Questions
What is CVE-2025-15646?
CVE-2025-15646 is a critical-severity vulnerability tracked under the Common Vulnerabilities and Exposures program. HTML::Gumbo versions before 0.19 for Perl disclose heap memory via type confusion.
Support for the element was added to libgumbo 0.10.0 in 2015, but the walk_tree function in lib/HTML/Gumb
Am I affected?
Affected technology is listed in the Affected Products section above. If your asset inventory contains any of them, assume in-scope until you can prove otherwise.
How urgent is the response?
Critical: do not wait for your normal patch cycle. Verify exposure today, apply the vendor patch immediately, and add detection rules for any post-exploit indicators.
How do I remediate?
Apply the vendor patch listed in the upstream advisory linked under Sources. If the patch is not yet available, follow the vendor-supplied workaround (often a config flag or feature disable) and add detections for the published exploit pattern in your SIEM. Re-scan after the patch lands to confirm the finding clears.
Where can I track exploitation activity?
Watch CISA's Known Exploited Vulnerabilities catalog for CVE-2025-15646. Cross-reference with public exploit databases and your own SIEM/IDS for indicator-of-compromise patterns. Vulnios tracks KEV status automatically and surfaces it on the asset findings view.
How does Vulnios help with this?
Vulnios continuously cross-references your asset inventory against the live CVE feed (NVD, vendor advisories, CISA KEV, and curated OSINT). When a new CVE matches your environment, you get a prioritized finding with the severity, KEV status, exploit-prediction (EPSS), and a direct path to the vendor patch. You can start a free scan from the homepage.
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