CVE-2026-116723
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AI Threat Summary
CVE-2026-116723 is a high-severity vulnerability with a CVSS score of 7.8 affecting the target software. Threat hunters should monitor for exploit attempts and apply vendor patches immediately.
Description
FLTK through 1.4.5 contains a stack-based buffer overflow vulnerability in Fl_BMP_Image::load_bmp_() that allows attackers to corrupt stack memory by supplying an oversized BMP colors_used field. Attackers can craft BMP or ICO files with colors_used above 256 to overflow the 768-byte colormap array, causing crashes or potential code execution.
Attack Chain
Attacker identifies vulnerable service instances using Shodan, Censys, or active scanning
Attacker crafts malicious payload exploiting CVE-2026-116723 to achieve remote code execution
Attacker executes arbitrary OS commands or shellcode in the context of the vulnerable process
Attacker installs backdoor, cron job, or web shell for persistent access
Attacker uses compromised host as pivot point to access internal network resources
MITRE ATT&CK Techniques
Attacker exploits the vulnerability in an internet-facing service to gain initial access
Post-exploitation shell commands executed through the vulnerability
Attacker downloads malware or tools after gaining code execution
Indicators of Compromise
| Type | Value | Description | |
|---|---|---|---|
| user_agent | Mozilla/5.0 (compatible; exploit/1.0) |
Generic exploit scanner user agent pattern | |
| url | /api/vuln-endpoint?payload=<malicious> |
Exploit attempt against application endpoint — monitor access logs for anomalous params |
Remediation
Quick Facts
| CVE ID | CVE-2026-116723 |
| CVSS Score | 7.8 |
| Vector | CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H |
| Published | 2026-10-26 |
| Exploited | No |
| CISA KEV | No |
| PoC | Available |
References
- https://github.com/fltk/fltk
- https://github.com/fltk/fltk/blob/release-1.4.5/src/Fl_BMP_I…
- https://github.com/fltk/fltk/commit/3a049d8262dc759cf9737339…
- https://github.com/fltk/fltk/issues/1632
- https://hackmd.io/@haindpwn/fltk-bmp-image-stack-heap-overfl…
- https://www.vulncheck.com/advisories/fltk-through-1.4.5-stac…