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Foxit PDF Editor/Reader EUVDEUVD-2026-85120

| CVE-2026-91802 MEDIUM
Out-of-bounds Write (CWE-787)
2026-09-23 Foxit GHSA-vm9v-2x45-2rm4
5.5
CVSS 3.1 · NVD
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Attack ChainAIDerived

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

  1. Access
    Craft malicious WebP-embedded PDF
  2. Delivery
    Deliver via email or download link
  3. Exploit
    Victim opens file in Foxit
  4. Execution
    Trigger heap OOB write in WebP decoder
  5. Impact
    Corrupt memory / crash application

Vulnerability Assessment

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

2 techniques across 2 tactics: Execution, Privilege Escalation

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

Exploitation Conditions

Exploitation requires a victim to open or render an attacker-controlled PDF containing a crafted WebP image whose bitmap stride and target buffer format are manipulated to trigger the OOB write in Foxit's WebP decoding path (UI:R). It is local/client-side (AV:L): the attacker must deliver the file and rely on the user opening it in Foxit PDF Editor or Reader - there is no server-side or network-listening component. No application authentication is needed (PR:N), but the user-interaction and file-delivery requirement is the primary limiting factor, along with dependence on the specific vulnerable Foxit versions.

Impact

This is a client-side, file-format parsing memory-corruption bug (CWE-787 heap out-of-bounds write in WebP decoding) requiring local access and user interaction: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H (7.8). PR:N here means no application authentication is required, but exploitation is NOT remote-unauthenticated in the network sense - the AV:L/UI:R combination means a victim must open or render an attacker-supplied PDF (or embedded WebP), so real-world risk is gated on social engineering rather than mass remote scanning. There is a notable conflict between the vendor CVSS impact (C:H/I:H/A:H, implying arbitrary code execution) and the description, which states only that 'successful exploitation could result in an application crash' (availability impact) - verify with Foxit whether code execution is actually achievable, as OOB writes are frequently exploitable but this advisory scopes impact to a crash. No EPSS score, no CISA KEV listing, and no public POC are present in the provided data, so there is no evidence of active or automated exploitation; this reads as a routine hardening/patch-now-on-cycle client vulnerability rather than an emergency, despite the 7.8 score.

Exploit ScenarioDerived

An attacker crafts a malicious PDF (or a document embedding a malformed WebP image) with manipulated bitmap stride/target-buffer format fields and delivers it via email or a download link. When the victim opens the file in Foxit PDF Editor/Reader, the WebP decoder performs a heap out-of-bounds write, corrupting memory and at minimum crashing the application (potential for code execution per the CVSS impact metrics). No public exploit code was identified in the provided data.

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 write in Foxit PDF Editor/Reader allows attackers to corrupt memory when a victim opens a PDF containing a crafted WebP image, potentially leading to code execution or a crash. The flaw stems from improper handling of bitmap stride and target buffer formats (CWE-787) and requires user interaction to open the malicious file (CVSS 7.8, AV:L/PR:N/UI:R). No public exploit code or active exploitation has been identified at time of analysis.

RemediationAI

Patch available per vendor advisory: apply the latest update from Foxit's security bulletins page (https://www.foxit.com/support/security-bulletins.html) to address CVE-2026-91802. Because no exact fixed version is provided in the input data, consult the advisory for the precise patched release. Until patching is possible, avoid opening PDFs from untrusted sources or containing unknown WebP images; if your deployment allows, consider disabling WebP image rendering within Foxit, though this may break legitimate documents. Deploying exploit mitigation technologies such as ASLR and DEP can make exploitation harder but do not eliminate the vulnerability. No public exploit code or active exploitation has been identified, so the immediate risk is lower, but timely patching remains the primary defense.

Affected VersionsENISA

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

Affects your stack

Find out whether the stacks and servers you run are on an affected version.

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

Technical ContextAI · show details

This vulnerability resides in Foxit's WebP image decoding implementation, specifically in how it handles bitmap stride (the number of bytes per row of a bitmap) and target buffer formats. When a crafted WebP image embedded in a PDF is parsed, mismatched stride or format calculations cause a heap-based out-of-bounds write (CWE-787). The affected products are Foxit PDF Editor and Foxit PDF Reader, as indicated by CPE strings cpe:2.3:a:foxit_software_inc.:foxit_pdf_editor:*:*:*:*:*:*:*:* and cpe:2.3:a:foxit_software_inc.:foxit_pdf_reader:*:*:*:*:*:*:*:*. WebP is a modern image format developed by Google, and PDF documents can embed such images; Foxit's decoder fails to properly validate buffer size expectations when converting or rendering the WebP data.

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

Vendor (Foxit) PRIMARY HIGH
NVD 5.5 MEDIUM
AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
vuln.today AI 7.8 HIGH

AV:L/UI:R because the victim must open a malicious file; PR:N as no app auth is needed; impact retained at C:H/I:H/A:H per vendor for the OOB write, though the description confirms only a crash.

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

Primary rating from Vendor (Foxit).

CVSS VectorNVD

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

Lifecycle Timeline

3
Severity Changed
Oct 08, 2026 - 14:07 NVD
HIGH MEDIUM
CVSS changed
Oct 08, 2026 - 14:07 NVD
7.8 (HIGH) 5.5 (MEDIUM)
CVE Published
Sep 23, 2026 - 07:50 cve.org
HIGH 7.8

DescriptionNVD

A heap-based out-of-bounds write vulnerability exists in Foxit PDF Editor/Reader’s WebP image decoding due to improper handling of bitmap stride and target buffer formats. Successful exploitation could result in an application crash.

Executive ViewAI

Why It Matters

A high-severity memory-corruption vulnerability in Foxit PDF Editor and Foxit PDF Reader can let an attacker run code on a user's machine when that user opens a PDF carrying a crafted WebP image, a routine action in most document-heavy workflows. Any employee who opens such a file - whether received by email, downloaded from the web, or pulled from a shared repository - could be affected, making this a broad endpoint risk wherever Foxit is the default PDF application. Exploitation requires the user to open the file, and no public exploit code has been identified at time of analysis, so this is a near-term exposure to manage rather than an active incident, but the absence of a vendor patch means the organization cannot close it through routine patching alone.

Business Impact: High
Compensating Controls

No vendor-released patch identified at time of analysis. Interim mitigations: route all externally sourced PDF attachments through email/web sandboxing or detonation before delivery; block or strip embedded WebP image objects from inbound PDFs at the gateway; enable exploit-mitigation features (ASLR, DEP, CFG/CET, Microsoft Defender Exploit Guard or equivalent) for Foxit executables; restrict Foxit to users with a genuine business need and set an alternative hardened PDF reader as default elsewhere; disable browser and mail-client in-line PDF preview so files open only in the standalone application; apply application allow-listing and monitor for Foxit spawning unexpected child processes; maintain user awareness guidance against opening unsolicited PDFs; track Foxit's advisory feed for a fixed build and apply it immediately once released.

Threat Intelligence Overview

EPSS Score
0.2%
Top 93% exploitable
Prevalence
High
Foxit is among the most widely deployed PDF reader/editor alternatives to Adobe
Data Quality
6 sources
Confidence: High

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
Scheduled
Exploitation
None
System Exposure· derived
Small
Automatable
No
Human Impact
High
Technical Impact
Total

Priority Score

28
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +28
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.

Memory corruption occurs when a program writes data beyond the boundaries of allocated memory regions or accesses memory in unintended ways, violating the integrity of the process's address space.

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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