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Full vulnerability report · 2026
CVE-2026-34621High confidence

Adobe Acrobat and Reader Prototype Pollution Vulnerability

Adobe · Acrobat and Reader

Official source article: Adobe APSB26-43 ↗. Check the applicable product and release in the original source.

8.6HighCVSS 3.1
Recommended action
Patch now

CISA confirms exploitation in the wild and lists 2026-04-27 as the remediation due date.

Patch available
R
Operational reassessment

Published severity in operational context

Open reassessment dashboard →
Published severityHighOperational priority:Critical, raised one band.upgradedsince 13 Apr 2026

Evidence used

  • CISA confirms exploitation in the wild.
  • EPSS is 2.18% for the current model date.

Compensating controls

  • Validate the affected product branch and deploy the verified fixed release.
  • Restrict local access and enforce least privilege on affected hosts.
  • Increase monitoring for the attack path and post-exploitation behaviour described in the report.

Verification

  1. Confirm that the asset runs Adobe Acrobat and Reader and falls inside the recorded affected range.
  2. Verify the installed build against the product-specific fixed version after deployment.
  3. Validate exposure, authentication requirements and compensating controls in the actual environment.
  4. Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Mitigation target: Within 3 daysRemediation target: Within 90 days

This automated reassessment organises public evidence. It does not know asset exposure, business impact or control effectiveness and does not replace CVSS or a human risk decision.

Optional official sources

National CERT insights
?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

Choose official national sources for this report. Each advisory shows its original language. Your selection is remembered on this device and included in shared links.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current
ENISA EUVD identifier

EUVD-2026-21675

CISA KEV mirrored by ENISA

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.

EUVD state
Present in the current official mapping
Known exploitation
Recorded by ENISA since 13 Apr 2026. Evidence sources: cisa_kev.
ENISA score
8.6 · CVSS 3.1
Advisory evidence
2 linked advisory records
Explicit mitigation evidence

Only statements that explicitly mention a fix, patch, update, workaround or mitigation are shown here.

  • csaf_ncscnl · NCSC-2026-0111Kwetsbaarheid verholpen in Adobe Acrobat
Recommended actionPatch now

CISA confirms exploitation in the wild and lists 2026-04-27 as the remediation due date.

Patch available
01

What, why and how

Adobe Acrobat and Reader contain a prototype pollution vulnerability that allows for arbitrary code execution.

What

Adobe Acrobat and Reader contain a prototype pollution vulnerability that allows for arbitrary code execution.

Why

The product receives input from an upstream component that specifies attributes that are to be initialized or updated in an object, but it does not properly control modifications of attributes of the object prototype.

How

An attacker operating through local access may attempt exploitation without authentication after a user interaction. If successful, the issue may execute code or commands in the affected security context.

What

Adobe Acrobat and Reader contain a prototype pollution vulnerability that allows for arbitrary code execution.

Why

The product receives input from an upstream component that specifies attributes that are to be initialized or updated in an object, but it does not properly control modifications of attributes of the object prototype.

How

An attacker operating through local access may attempt exploitation without authentication after a user interaction. If successful, the issue may execute code or commands in the affected security context.

02

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
Confirmed in the wild

CISA added this CVE to its Known Exploited Vulnerabilities catalogue on 2026-04-13.

Public PoC / exploit material
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
None recorded

No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.

Likely attack path
local access → Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution') → execute code or commands in the affected security context
Attack surface
Local
Privileges required
None: unauthenticated exploitation is possible
User interaction
Required interaction required
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Changed: exploitation can affect a different security authority
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-1321 ↗

CWE-1321: Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution'). The product receives input from an upstream component that specifies attributes that are to be initialized or updated in an object, but it does not properly control modifications of attributes of the object prototype.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H

Common Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.

AVLocalAttack vector: The attacker needs local access to the vulnerable system.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRNonePrivileges required: The attacker does not need an account or existing privileges.UIRequiredUser interaction: Another user must perform an action for exploitation to succeed.SChangedScope: The attack can affect a component governed by a different security authority.CHighConfidentiality impact: A successful attack can cause a major loss.IHighIntegrity impact: A successful attack can cause a major loss.AHighAvailability impact: A successful attack can cause a major loss.
Post-exploitation / living off the land
After compromise, an attacker may use built-in shells, scripting engines, scheduled tasks and native network utilities for discovery, persistence or movement. This is a plausible LoTL path, not evidence that it has occurred for every attack.
UnauthenticatedRemote code executionCWE-1321CISA KEV
A

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

ENISA EUVD · EUVD-2026-21675Known-exploited evidence recorded

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.

Official EUVD record ↗
BSI · German · WID-SEC-2026-1047Adobe Acrobat Reader: Schwachstelle ermöglicht Offenlegung von Informationen und Codeausführung

Ein lokaler Angreifer kann eine Schwachstelle in Adobe Acrobat Reader ausnutzen, um vertrauliche Informationen offenzulegen und beliebigen Code auszuführen, was zu einer vollständigen Kompromittierung des Systems führen könnte.

Official advisory ↗
Canadian Centre for Cyber Security · English · AV26-340Adobe Acrobat security advisory (AV26-340) – Update 1

On April 12, 2026, Adobe published a security advisory to address a critical vulnerability in the following products: Adobe is aware of CVE-2026-34621 being exploited in the wild.

Official advisory ↗
Cyber Security Agency of Singapore · English · CSA-SB-20260415Security Bulletin 15 April 2026

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 15 April 2026, published on 15 April 2026. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
CERT-FR · French · CERTFR-2026-AVI-0429Vulnérabilité dans Adobe Acrobat

Une vulnérabilité a été découverte dans Adobe Acrobat. Elle permet à un attaquant de provoquer une exécution de code arbitraire. Adobe indique que la vulnérabilité CVE-2026-34621 est activement exploitée.

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2026-010940アドビのAdobe Acrobat等の複数製品におけるオブジェクトプロトタイプ属性の不適切に制御された変更に関する脆弱性

Acrobat Readerのバージョン24.001.30356、26.001.21367およびそれ以前のバージョンは、オブジェクトプロトタイプ属性の不適切な制御（「プロトタイプ汚染」）の脆弱性に影響を受けており、これにより現在のユーザーのコンテキストで任意のコードを実行される可能性があります。この問題を悪用するには、被害者が悪意のあるファイルを開くというユーザーの操作が必要です。

Official advisory ↗
KISA KrCERT/CC · Korean · KNVD-6757Adobe 제품 보안 업데이트 권고

Acrobat DC, Acrobat Reader DC, Acrobat 2024에서 발생하는 Prototype Pollution 취약점(CVE-2026-34621) [1][2]

Official advisory ↗
KISA KrCERT/CC · Korean · KNVD-6758美 CISA 발표 주요 Exploit 정보공유(Update. 2026-04-13)

Adobe Acrobat and Reader Prototype Pollution Vulnerability

Official advisory ↗
NCSC-NL · Dutch · NCSC-2026-0111Kwetsbaarheid verholpen in Adobe Acrobat

Acrobat Reader versions 24.001.30356, 26.001.21367, and earlier contain a Prototype Pollution vulnerability that may allow arbitrary code execution when a user opens a malicious file.

Official advisory ↗
03

Patch and workaround

Operational remediation based on structured source evidence.

Status
?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Patch available
Affected
Fixed
Action
Review the linked authoritative reference and apply the recorded fixed release appropriate to the affected product branch.
Workaround
No verified workaround is recorded. Limit untrusted access and use least privilege until authoritative guidance is available.
Official vendor articles1 stored document

Linked articles are downloaded and versioned as source evidence. A CVE mention or approved update relationship does not, by itself, verify a fix for every product branch.

  • Security update available for Adobe Acrobat Reader | APSB26-43 →Original publisher ↗Searchable text snapshot · Captured 27 Sep 2026#202020 Adobe Security Bulletin Last updated on Apr 12, 2026 Security update available for Adobe Acrobat Reader | APSB26-43 Bulletin ID Date published Priority APSB26-43 April 11, 2026 1 style grid width 12 Summary Adobe has released a security update for Adobe Acrobat and Reader for Windows and macOS. This update
04

Evidence and provenance

Published 11 Apr 2026 · Last source change 27 Aug 2026, 22:15 UTC · CWE-1321 · Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')

CVE recordCVE.org · 5.2
CVSS sourceCNA
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-08-14
European sourceENISA EUVD · EUVD-2026-21675
Product sourceCISA KEV
Remediation sourceCVE/CNA references
CWE sourceCNA
NVD statusNVD enriched

Core structured fields are present and their contributing authorities are shown above.

Material change intelligence

What changed after publication

View recent updates ↗
  1. Affected versionsThe structured affected or fixed version information changed.
    Before
    ≤ 26.001.21367; ≤ 24.001.30356 · Fixed: 26.001.21411; 24.001.30362 (Win), 24.001.30360 (Mac)
    After
    Acrobat DC: ≤ 26.001.21367; Acrobat Reader DC: ≤ 26.001.21367; Acrobat 2024: ≤ 24.001.30356 · Fixed: Acrobat DC: 26.001.21411; Acrobat Reader DC: 26.001.21411; Acrobat 2024: 24.001.30362 (Win), 24.001.30360 (Mac)
    CNA ↗
  2. Vendor guidanceAuthoritative vendor guidance changed: added remediation: helpx.adobe.com/apsb26-43.html.
    Before
    vendor advisory: helpx.adobe.com/apsb26-43.html
    After
    remediation: helpx.adobe.com/apsb26-43.html · vendor advisory: helpx.adobe.com/apsb26-43.html
    psirt@adobe.com ↗
  3. Affected versionsThe structured affected or fixed version information changed.
    Before
    ≤ 26.001.21367 · Fixed: No fixed version is explicitly recorded in the structured CVE data.
    After
    ≤ 26.001.21367; ≤ 24.001.30356 · Fixed: 26.001.21411; 24.001.30362 (Win), 24.001.30360 (Mac)
    CNA ↗
  4. Remediation statusRemediation status changed from Awaiting fix to Patch available.
    Before
    Awaiting fix
    After
    Patch available
    psirt@adobe.com ↗
Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
Added to CISA KEV
Fixed release or patch reference recorded
ENISA EUVD · EUVD-2026-21675↗CISA KEV record↗CVE authority or vendor reference · Adobe APSB26-43↗Official CVE record (CNA and ADP data)↗NVD record↗
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
Free version - for non-commercial use only.CVE-2026-34621 · cve.blacktree.nl