CVE-2026-34621
HIGHCISA KEVEPSS 94th pctlDescription
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.
How to fix
TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works
Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.
CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
Exploit Intelligence
High risk: more likely to be exploited than 94% of all known CVEs.
Remediation due: 2026-04-27
References
Related Vulnerabilities
Other CWE-1321 vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2019-0230 | Critical | 9.8 | 97% | - | - |
| CVE-2019-11358 | Medium | 6.1 | 87% | - | Fix |
| CVE-2020-7774 | High | 7.3 | 69% | - | Fix |
| CVE-2022-24760 | Critical | 10.0 | 49% | - | Fix |
| CVE-2022-39396 | Critical | 9.8 | 39% | - | Fix |
| CVE-2022-2564 | Critical | 9.8 | 33% | - | Fix |
Common questions
How do I fix CVE-2026-34621?
Published advisories record a fix for 4 affected products. The "How to fix" section on this page lists the fixed version and source advisory for each one, so apply the entry matching what you actually run.
Is CVE-2026-34621 being actively exploited?
Yes. CVE-2026-34621 is listed in the CISA Known Exploited Vulnerabilities catalog, which means exploitation has been observed in the wild. US federal agencies were required to remediate it by 2026-04-27. Treat it as a priority whatever its CVSS score says.
How severe is CVE-2026-34621?
CVE-2026-34621 has a CVSS v3 base score of 8.6, rated high. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
What does CVE-2026-34621 affect?
Published advisories record a fix for 64-bit (Windows application), Adobe Acrobat 2020 (Windows application), Adobe Acrobat Pro (Windows application), Adobe Acrobat Reader (32-bit) (Windows application). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-04-13.