VulnerabilityPublished 25 Jun 2025

CVE-2025-6646: PDF-XChange Editor · Use After Free

Affects PDF-XChange EditorSource CVE Database V5

Not known to be exploited · CVSS 3.3 Low.

Data as of 26 Oct 2026, 14:05 UTC

CVSS 3.0 base score

3.3Low

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.2% chance of exploitation in 30 days – higher than 17% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N

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

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Local: The vulnerable component is not bound to the network stack and the attacker’s path is via read/write/execute capabilities. Either: the attacker exploits the vulnerability by accessing the target system locally (e.g., keyboard, console), or remotely (e.g., SSH); or the attacker relies on User Interaction by another person to perform actions required to exploit the vulnerability (e.g., tricking a legitimate user into opening a malicious document).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: Required: Successful exploitation of this vulnerability requires a user to take some action before the vulnerability can be exploited.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the impacted component.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 25 Jun 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
PDF-XChange PDF-XChange Editor	Affected =10.5.2.395	Fixed in–

AI-suggested

Implement strict email and web filtering to block or quarantine suspicious PDF files, especially those containing embedded 3D content (U3D files).
Educate users to be cautious when opening PDF attachments or clicking links from unknown or untrusted sources, emphasizing the risks of embedded 3D content.
Employ endpoint detection and response (EDR) solutions capable of monitoring and alerting on anomalous behaviors related to PDF processing or memory corruption attempts.
Restrict the use of PDF-XChange Editor to trusted users and consider sandboxing or application containment techniques to limit the impact of potential exploitation.
Monitor vendor communications closely for patches or updates addressing this vulnerability and prioritize timely application once available.
Use network segmentation to isolate systems that handle sensitive documents and limit exposure if compromise occurs.
Consider deploying application whitelisting to prevent execution of unauthorized or suspicious PDF-related processes. These measures go beyond generic advice by focusing on controlling the attack vector (malicious PDFs with U3D content), user behavior, and containment strategies specific to this vulnerability's exploitation method.

Description

PDF-XChange Editor U3D File Parsing Use-After-Free Information Disclosure Vulnerability. This vulnerability allows remote attackers to disclose sensitive information on affected installations of PDF-XChange Editor. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file. The specific flaw exists within the parsing of U3D files. The issue results from the lack of validating the existence of an object prior to performing operations on the object. An attacker can leverage this in conjunction with other vulnerabilities to execute arbitrary code in the context of the current process. Was ZDI-CAN-26643.

Impact

For European organizations, the primary impact of CVE-2025-6646 is the potential disclosure of sensitive information from memory when users open malicious PDF files or visit malicious web pages. Although the immediate impact is limited to information disclosure, the vulnerability's ability to be chained with other exploits raises the risk of arbitrary code execution, which could lead to system compromise, data theft, or lateral movement within networks. Organizations handling sensitive or confidential information, such as financial institutions, government agencies, and critical infrastructure operators, could face increased risks if attackers leverage this vulnerability as part of a multi-stage attack. However, the requirement for user interaction and the low severity rating reduce the likelihood of widespread exploitation. The lack of known exploits in the wild further limits immediate risk but does not eliminate the need for vigilance. Given the widespread use of PDF-XChange Editor in various sectors across Europe, especially in professional and administrative environments, the vulnerability could be leveraged in targeted phishing campaigns or watering hole attacks aimed at high-value targets.

CWE-416Use After Free (opens in a new tab)
Variant weaknessLikelihood of exploit: HighCWE Top 25 (2025): #7
The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.
Architecture and Design · Language Selection
Choose a language that provides automatic memory management.
Implementation · Attack Surface Reduction
When freeing pointers, be sure to set them to NULL once they are freed. However, the utilization of multiple or complex data structures may lower the usefulness of this strategy.
OWASP Cheat Sheets
XML Security (opens in a new tab)
Mass Assignment (opens in a new tab)
OWASP ASVS 4.0.3
V13.3.1 (opens in a new tab)
V5.1.4 (opens in a new tab)
V5.1.3 (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 25 Jun 2025, 22:30 UTC

WeaknessesCWE-416

Technical details

References

Community reviews

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