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CVE-2026-34621

High Vulnerability: CVE-2026-34621 — adobe, apple — acrobat_dc, acrobat_reader_dc

CISA Known Exploited Vulnerability — Immediate Action Required

Acrobat Reader versions 24.001.30356, 26.001.21367 and earlier are affected by an Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution') vulnerability that could result in arbitrary code execution in the context of the current user. Exploitation of this issue requires user interaction in that a victim must open a malicious file.

Tuesday, April 14, 2026adobe, appleVulnios Threat Intelligence
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Vulnerability Snapshot

CVE-2026-34621 is rated HIGH — exploitation is straightforward for a motivated attacker and impact is significant. Apply the vendor patch within your standard high-severity SLA.

This vulnerability appears in CISA's Known Exploited Vulnerabilities (KEV) catalog, meaning it has been observed in active attacks. Federal agencies have a remediation deadline; commercial defenders should treat it with equivalent urgency.

Affected technology: acrobat_dc, acrobat_reader_dc, macos, windows, acrobat.

Executive Summary

Acrobat Reader versions 24.001.30356, 26.001.21367 and earlier are affected by an Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution') vulnerability that could result in arbitrary code execution in the context of the current user. Exploitation of this issue requires user interaction in that a victim must open a malicious file.

Why It Matters

CVE-2026-34621 is rated HIGH severity, requiring immediate attention from security teams.

⚠️ This vulnerability is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, indicating it has been actively exploited in the wild. Federal agencies must remediate by the deadline.

CVSS Base Score: 8.6/10

EPSS (Exploit Prediction): 0.0% probability of exploitation in the next 30 days.

Affected Technologies

Vendors: adobe, apple, microsoft

Products: acrobat_dc, acrobat_reader_dc, macos, windows, acrobat

🛡️What Defenders Should Check

  • Check if you are affected — Review your asset inventory for products listed in CVE-2026-34621.
  • Apply available patches — Visit vendor advisories for the latest security updates.
  • Monitor for exploitation — Check your SIEM/IDS logs for related indicators.
  • Prioritize remediation — This is a CISA KEV entry. Federal agencies: remediate by the mandated deadline.
  • CISA Deadline: 2026-04-27

    • Use Vulnios to continuously monitor your exposure to CVE-2026-34621 and similar vulnerabilities.

    References & Sources

  • https://helpx.adobe.com/security/products/acrobat/apsb26-43.html
  • https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-34621

    • How Vulnios Detects This

    Vulnios scans for this vulnerability using KEV cross-check that flags any host where this CVE is already on CISA's exploited list. 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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    Affected Products

    acrobat_dcacrobat_reader_dcmacoswindowsacrobat

    Sources

    Related Threat Alerts

    Frequently Asked Questions

    What is CVE-2026-34621?

    CVE-2026-34621 is a high-severity vulnerability tracked under the Common Vulnerabilities and Exposures program. Acrobat Reader versions 24.001.30356, 26.001.21367 and earlier are affected by an Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution') vulnerability that could res

    Am I affected?

    Check whether your environment runs acrobat_dc, acrobat_reader_dc, macos, windows, acrobat. If you operate any of those, treat yourself as in scope until you have evidence otherwise. A Vulnios scan will identify the exact assets carrying the affected version.

    How urgent is the response?

    High: address inside your standard high-severity SLA (typically 7 days for internet-exposed assets, 30 days for internal). Skip ahead in the queue if the host is internet-facing.

    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-2026-34621. 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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