FastStone Image Viewer up to 8.3.0.0 JP2 Decoder FSViewer.exe heap-based overflow

CVSS Meta Temp Score
CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.
Current Exploit Price (≈)
Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.
CTI Interest Score
Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
6.3$0-$5k5.61-

Summaryinfo

A vulnerability was found in FastStone Image Viewer up to 8.3.0.0. It has been declared as critical. Affected is an unknown function of the file FSViewer.exe of the component JP2 Decoder. Executing a manipulation can lead to heap-based overflow. This vulnerability is registered as CVE-2026-30040. It is possible to launch the attack remotely. No exploit is available.

Detailsinfo

A vulnerability has been found in FastStone Image Viewer up to 8.3.0.0 and classified as critical. This vulnerability affects some unknown processing of the file FSViewer.exe of the component JP2 Decoder. The manipulation with an unknown input leads to a heap-based overflow vulnerability. The CWE definition for the vulnerability is CWE-122. A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc(). As an impact it is known to affect confidentiality, integrity, and availability.

The advisory is available at kb.cert.org. This vulnerability was named CVE-2026-30040. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. Successful exploitation requires user interaction by the victim. Technical details are known, but there is no available exploit. The structure of the vulnerability defines a possible price range of USD $0-$5k at the moment (estimation calculated on 06/23/2026).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

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Productinfo

Vendor

Name

Version

License

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 6.3
VulDB Meta Temp Score: 6.3

VulDB Base Score: 6.3
VulDB Temp Score: 6.3
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Heap-based overflow
CWE: CWE-122 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔒

Timelineinfo

06/23/2026 Advisory disclosed
06/23/2026 +0 days VulDB entry created
06/23/2026 +0 days VulDB entry last update

Sourcesinfo

Advisory: kb.cert.org
Status: Not defined

CVE: CVE-2026-30040 (🔒)
GCVE (CVE): GCVE-0-2026-30040
GCVE (VulDB): GCVE-100-372910

Entryinfo

Created: 06/23/2026 16:36
Changes: 06/23/2026 16:36 (49), 06/23/2026 16:37 (2)
Complete: 🔍
Cache ID: 216::103

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