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Foxit PDF Editor EUVDEUVD-2026-85157

| CVE-2026-91817 MEDIUM
Out-of-bounds Read (CWE-125)
2026-09-23 Foxit GHSA-pg53-55p8-5cr6
6.1
CVSS 3.1 · Vendor: Foxit
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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

  1. Access
    Craft PDF with malicious embedded JavaScript
  2. Delivery
    Deliver file to victim via email or download
  3. Exploit
    Victim opens PDF in Foxit
  4. Execution
    Integer underflow in string-deletion range
  5. Persist
    Out-of-bounds heap read
  6. Impact
    Memory disclosure and application crash

Vulnerability Assessment

Weakness
CWE
ASVS 5.0
V15 - Secure Coding and Architecture Bounds checking, read limits
MITRE ATT&CK

1 technique across 1 tactic: Collection

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

Exploitation Conditions

Exploitation requires the victim to open an attacker-crafted PDF containing embedded JavaScript in Foxit PDF Editor or Reader; the malicious JavaScript must perform a wide-string deletion with an out-of-range value that triggers the integer underflow. Limiting factors: the CVSS vector is local (AV:L) and requires user interaction (UI:R), so there is no remote or unauthenticated network exploitation - the attacker depends on social engineering to get the file opened, and JavaScript execution must be enabled in the reader. Impact is capped at limited memory disclosure and a crash (no code execution or integrity impact claimed).

Impact

This is a genuine but modest-severity issue. The CVSS 3.1 vector (6.1, AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:H) describes a file-borne bug: the attacker cannot reach the victim over the network - the local attack vector plus UI:R means a user must open a malicious PDF. Impact is limited to a small confidentiality leak (C:L, from the out-of-bounds read) and application crash/denial of service (A:H); there is no integrity impact and no code execution claimed. CWE-125 (out-of-bounds read) is consistent with the description of an integer underflow in string-deletion range validation. No EPSS score, no CISA KEV listing, and no public POC were provided, so there is no evidence of active or automated exploitation. The signals are internally consistent: an OOB read that crashes the app but may disclose limited adjacent heap memory. This is a real defect worth patching, but not a high-priority emergency - real-world risk is bounded by the need for user interaction, the local vector, and the absence of RCE or exploitation evidence. Note: this was vendor-reported (Foxit) with only a generic security-bulletins reference, so exact affected/fixed versions are not confirmed from the provided data.

Exploit ScenarioDerived

An attacker crafts a PDF containing embedded JavaScript that manipulates wide strings with a malformed deletion range, triggering an integer underflow. The attacker delivers the file via email or download and social-engineers the victim into opening it in Foxit PDF Editor/Reader, causing an out-of-bounds read that leaks limited heap memory and crashes the application. No public exploit was identified at time of analysis.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).
No patch listed yet 0.2% exploitation probability (EPSS)

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AnalysisAIv1 – Sep 23, 2026

Heap-based out-of-bounds read in Foxit PDF Editor and Foxit PDF Reader can crash the application and may disclose limited heap memory contents when a user opens a crafted PDF containing embedded JavaScript that triggers an integer underflow during a wide-string deletion operation. Exploitation is local and requires user interaction: the victim must open the malicious PDF and JavaScript execution must be enabled, and the CVSS vector (CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:H) indicates no privileges are required but no remote network path. No public exploit identified at time of analysis; confidentiality impact is low and availability impact is high, making this a modest-severity issue that primarily causes denial of service.

RemediationAI

The provided data does not identify a vendor-released patch or fixed version; consult Foxit's security bulletins page at https://www.foxit.com/support/security-bulletins.html for an updated advisory and patched release. Because the exploit path depends on embedded PDF JavaScript, a compensating control is to disable JavaScript execution in Foxit PDF Editor/Reader (typically under File > Preferences > JavaScript, uncheck 'Enable JavaScript Actions' or equivalent); this blocks the vulnerable wide-string code path but will break interactive forms, calculations, and other scripted PDF features. Additional mitigations include treating untrusted PDFs with caution, opening them in a sandboxed or restricted environment, and using mail/file filtering to reduce social-engineering delivery. When Foxit publishes a fix, apply it promptly; the local, user-interaction-required attack vector makes endpoint user awareness and safe-document-handling policies important interim controls.

Affected VersionsENISA

Foxit PDF Editor Versions 13.2.6 and earlier
Foxit PDF Editor Versions 14.0.7 and earlier
Foxit PDF Reader Versions 2026.2 and earlier
Foxit PDF Editor Versions 2026.2 and earlier

Affects your stack

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Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

The vulnerability is CWE-125 (out-of-bounds read) in Foxit PDF Editor and Foxit PDF Reader's JavaScript engine, specifically in handling wide strings embedded in PDF JavaScript. PDFs may include JavaScript for forms and dynamic content; when script code invokes a wide-string deletion operation with an out-of-range length or range value, insufficient validation causes an integer underflow. The underflowed value bypasses bounds checks and leads to a heap out-of-bounds read, which can crash the application and, under the CVSS C:L rating, potentially expose limited heap memory. CPE data lists cpe:2.3:a:foxit_software_inc.:foxit_pdf_editor:*:*:*:*:*:*:*:* and cpe:2.3:a:foxit_software_inc.:foxit_pdf_reader:*:*:*:*:*:*:*:*, indicating both products are in scope; the wildcard version fields mean exact affected version ranges are not specified in the supplied CPE data and should be confirmed in Foxit's advisory.

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Severity by source

Vendor (Foxit) PRIMARY 6.1 MEDIUM
AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:H
vuln.today AI 6.1 MEDIUM

File-borne bug requiring the victim to open a malicious PDF, so AV:L and UI:R with no privileges (PR:N); OOB read yields limited disclosure (C:L) and a crash (A:H), no integrity impact.

3.1 AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:H
4.0 AV:L/AC:L/AT:N/PR:N/UI:P/VC:L/VI:N/VA:H/SC:N/SI:N/SA:N

Primary rating from Vendor (Foxit).

CVSS VectorVendor: Foxit

Attack Vector
Local
Attack Complexity
Low
Privileges Required
None
User Interaction
Required
Scope
Unchanged
Confidentiality
Low
Integrity
None
Availability
High

DescriptionCVE.org

A heap-based out-of-bounds read vulnerability exists in Foxit PDF Editor/Reader’s handling of wide strings in embedded PDF JavaScript. Insufficient validation of string-deletion ranges can cause an integer underflow, resulting in an out-of-bounds read and application crash.

Threat Intelligence Overview

EPSS Score
0.2%
Top 95% exploitable
Prevalence
High
Foxit is one of the most widely deployed PDF readers/editors after Adobe
Data Quality
5 sources
Confidence: Medium

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity MEDIUM
CISA KEV No
Public POC No
EPSS 0.2%
Patch available No
Active threat No
Deciding rule
MEDIUM severity (CVSS 4.0-6.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Scheduled
Exploitation
None
System Exposure· derived
Small
Automatable
No
Human Impact· derived
High
Technical Impact
Partial

Priority Score

30
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +30
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

A buffer overflow occurs when a program writes more data to a memory buffer than it was allocated to hold, causing the excess data to spill into adjacent memory regions.

Information disclosure occurs when an application unintentionally exposes sensitive data that aids attackers in reconnaissance or directly compromises security.

CVE-2026-91814 MEDIUM POC
5.3 Sep 23

Content spoofing in Foxit PDF Editor and Foxit PDF Reader allows remote attackers to alter visible content in incrementa

CVE-2026-91800 HIGH
8.8 Sep 23

Local privilege escalation in Foxit PDF Editor for macOS allows an attacker with a low-privilege foothold to execute arb

CVE-2026-91798 HIGH
8.8 Sep 23

A local privilege escalation vulnerability in the auto-update daemon shipped with Foxit PDF Editor and Foxit PDF Reader

CVE-2026-91812 HIGH
8.1 Sep 23

Man-in-the-middle attackers occupying the network path of Foxit PDF Editor and Foxit PDF Reader software-update traffic

CVE-2026-91797 HIGH
7.8 Sep 23

Path traversal in the attachment-handling logic of Foxit PDF Editor and Foxit PDF Reader lets a crafted PDF write an emb

CVE-2026-91794 HIGH
7.8 Sep 23

An out-of-bounds write (CWE-787) in the PDF rendering engine of Foxit PDF Editor and Foxit PDF Reader can be triggered w

CVE-2026-91789 HIGH
7.8 Sep 23

Out-of-bounds write in the U3D/GIF texture decoding path of Foxit PDF Editor and Foxit PDF Reader allows a crafted PDF t

CVE-2026-91801 HIGH
7.8 Sep 23

Insufficient validation of embedded-resource file paths in Foxit PDF Editor and Foxit PDF Reader (CVE-2026-91801) lets a

CVE-2026-91791 HIGH
7.8 Sep 23

Foxit PDF Editor and Reader can crash due to a use-after-free (CWE-416) when a user opens a specially crafted PDF that i

CVE-2026-91799 HIGH
7.8 Sep 23

Use-after-free in Foxit PDF Editor and Foxit PDF Reader (CWE-416) lets a specially crafted PDF trigger memory corruption

CVE-2026-91815 HIGH
7.8 Sep 23

Heap-based out-of-bounds write in Foxit PDF Editor and Foxit PDF Reader occurs when the products decode JPEG2000 image d

CVE-2026-91790 HIGH
7.8 Sep 23

A use-after-free in Foxit PDF Editor and Foxit PDF Reader can be triggered by opening a crafted PDF whose image objects

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