CVE Intelligence
Medium Memory corruption

CVE-2026-116463 — FastStone Image Viewer Box-Average Downsampler FUN_0062d96c out-of-bounds

A vulnerability was identified in FastStone Image Viewer up to 8.5. Affected is the function FUN_0062d96c of the component Box-Average Downsampler Engine. The manipulation leads to out-of-bounds read. It is possible to initiate the attack remotely. The vendor was contacted early about this disclosure but did not respond in any way.

Published Oct 26, 2026 · Updated Oct 26, 2026 · Sources: CVE Program (cve.org) e CISA ADP, NIST National Vulnerability Database, GitHub Security Advisories · CNA: VulDB

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.
How the score was calculated
  • Technical severity (medium)+3

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation
Not confirmed
Not in CISA KEV — an absence of record, not proof it is unexploited.
EPSS FIRST
—
No EPSS score.
Affects
FastStone
Image Viewer
CVSS base
6.3
Medium · 3 source(s)

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

  1. Identify exposed assets running the affected vendor/product/version combinations (FastStone Image Viewer).
  2. The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
  3. No fix documented in the sources: reduce exposure and monitor the vendor advisory.
  4. Exploitation requires user interaction: tighten email/web filtering and warn affected users.
  5. Search available logs for exploit probes matching the vulnerability class (memory corruption), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

VendorProductVersionsStatusSource
FastStone Image Viewer version 8.0version 8.1version 8.2version 8.3version 8.4version 8.5 Vulnerable CVE Program (cve.org) e CISA ADP

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
Required
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
Low

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

ScoreVersionSeverityExpl.ImpactScored by
5.3 CVSS 4.0 Medium — — cna@vuldb.com via NIST National Vulnerability Database
5.3 CVSS 4.0 Medium — — VulDB via CVE Program (cve.org) e CISA ADP
6.3 CVSS 3.1 Medium 2.8 3.4 cna@vuldb.com via NIST National Vulnerability Database
6.3 CVSS 3.1 Medium — — GitHub, Inc. via GitHub Security Advisories
6.3 CVSS 3.1 Medium — — VulDB via CVE Program (cve.org) e CISA ADP
6.3 CVSS 3.0 Medium — — VulDB via CVE Program (cve.org) e CISA ADP
7.5 CVSS 2.0 High 10.0 6.4 cna@vuldb.com via NIST National Vulnerability Database
7.5 CVSS 2.0 High — — VulDB via CVE Program (cve.org) e CISA ADP
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:L (score shown at the top: cna@vuldb.com)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-119 · Buffer Errors (Improper Restriction of Operations within Memory Bounds)

Other CVEs with this weakness →

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

  • Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
  • Correlate service crashes/restarts with inbound traffic; repeated crashes may indicate attempts.
web/proxy/WAF logsnetwork IDS/IPSendpoint telemetry (EDR)crash dumps

Timeline

What happened to this CVE, newest first.

  • 2026
  • Source status changed · Published → Awaiting Analysis
    Oct 26, 2026 · NIST National Vulnerability Database
  • Record published
    Oct 26, 2026
  • CVSS changed · 6.3
    Oct 26, 2026 · CVE Program (cve.org) e CISA ADP
  • Source status changed · → Published
    Oct 26, 2026 · CVE Program (cve.org) e CISA ADP
  • Record created in this database
    Oct 26, 2026 · CVE Program (cve.org) e CISA ADP
  • CVE published
    Oct 26, 2026 · VulDB

Source activity

Repeated readings are counted rather than listed.

  • 1× References added · Oct 26, 2026 – Oct 26, 2026
  • 1× Official description updated · Oct 26, 2026 – Oct 26, 2026

References

6 on the record

Elsewhere on this site

FastStone
every CVE for this vendor
Memory corruption
same class
CWE-119
other pages naming this weakness

Related CVEs (same products)

  • CVE-2026-101202 FastStone Image Viewer TGA Image out-of-bounds write 28d
  • CVE-2026-101203 FastStone Image Viewer 1bpp RLE Decoder out-of-bounds write 28d
  • CVE-2026-101204 FastStone Image Viewer TGA Image FSViewer.exe out-of-bounds 28d
  • CVE-2026-101205 FastStone Image Viewer PCX Decoder out-of-bounds 28d

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No FIRST EPSS score.
  • No fixed version, patch or mitigation documented.
  • No CISA SSVC assessment.
  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-116463 is "FastStone Image Viewer Box-Average Downsampler FUN_0062d96c out-of-bounds", rated Medium. It affects Image Viewer (FastStone); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 6.3 describes technical severity. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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