ExploitedIn CISA KEVFix available

CVE-2026-34621

Q: Is CVE-2026-34621 actively exploited?

Yes. CVE-2026-34621 is on the CISA Known Exploited Vulnerabilities (KEV) catalog, meaning it has been confirmed as actively exploited in the wild. CISA requires federal agencies to patch by 2026-04-27.

Q: What is the CVSS score for CVE-2026-34621?

CVE-2026-34621 has a CVSS v3 base score of 8.6 (HIGH severity), with vector string CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H.

Exploitation confirmed. First attested on 2026-04-13 by CISA-ADP, CISA KEV, GCVE · kevintel.

Published2026-04-11
Fixed in24.001.30362 · 24.001.30360
WeaknessCWE-1321

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

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.

Timeline

dates in UTC

2026-04-1107:16CVE publishedNVD
2026-04-13Added to the CISA KEV catalogCISA KEV
2026-04-13Listed as exploited by GCVEGCVE
2026-04-13Exploitation first reportedCISA KEV
2026-04-1317:05SSVC exploitation set to activeCISA-ADP
2026-10-2319:23First public proof of conceptPoC-in-GitHub

Observed activity

isMalicious corpus · updated 2026-10-23 18:48 UTC

Indicators tagged with this CVE, per day0 indicators over 7 days

Block these indicators

Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2026-34621?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2026-34621?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD

Adobe acrobatversion to verify

Branch	Affected	Fixed in	Source
24.x	≥ 24.0.0, < 24.001.30362	24.001.30362	NVD
24.x	≥ 24.0.0, < 24.001.30360	24.001.30360	NVD

Adobe acrobat dcversion to verify

Branch	Affected	Fixed in	Source
26.1	< 26.001.21411	26.001.21411	NVD

Adobe acrobat reader dcversion to verify

Branch	Affected	Fixed in	Source
26.1	< 26.001.21411	26.001.21411	NVD

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

Update Adobe acrobat to 24.001.30362 · 24.001.30360
CISA’s required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.due 2026-04-27

Advisories and patches

helpx.adobe.comVendor Advisory

Detection

read 2026-10-23 19:25 UTC

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: 5 repositories, unverifiedercihan/CVE-2026-34621KeulenR01/Remediate-AdobeAcrobat-CVE-2026-34621NULL200OK/cve_2026_34621_advancedercihan/CVE-2026-34621_PDF_SAMPLEazefzafyoussef/CVE-2026-34621

CISA Known Exploited Vulnerability

Date Added: 2026-04-13
Patch Due Date: 2026-04-27
Ransomware Use: Unknown
Required Action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

Sources

NVDCVE recordread 2026-10-23
CISA KEVKEV entry2026-04-13
GCVEexploitation2026-04-13
CISA-ADPSSVC decisionactive2026-04-13
OpenCVESSVC decisionactive—
CNACVSS 3.18.6read 2026-10-23
CNAweakness (CWE)CWE-1321read 2026-10-23
FIRST EPSSEPSS score2.2 %2026-10-22
PoC-in-GitHubproof of concept5read 2026-10-23

Technical details

CVSS v3 Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
Published: 2026-04-11
Last Modified: 2026-08-28
NVD status: Analyzed

Frequently asked questions

What is CVE-2026-34621?

Is CVE-2026-34621 actively exploited?

Yes. CVE-2026-34621 is on the CISA Known Exploited Vulnerabilities (KEV) catalog, meaning it has been confirmed as actively exploited in the wild. CISA requires federal agencies to patch by 2026-04-27.

What is the CVSS score for CVE-2026-34621?

CVE-2026-34621 has a CVSS v3 base score of 8.6 (HIGH severity), with vector string CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H.

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