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.
References7
- github.com/fltk/fltk
- github.com/fltk/fltk/blob/release-1.4.5/src/Fl_BMP_Image.cxx#L2…
- github.com/fltk/fltk/commit/3a049d8262dc759cf9737339420e8457e24…
- github.com/fltk/fltk/issues/1632
- hackmd.io/@haindpwn/fltk-bmp-image-stack-heap-overflow
- www.vulncheck.com/advisories/fltk-through-1.4.5-stack-buffer-ov…
- hackmd.io/@haindpwn/fltk-bmp-image-stack-heap-overflow
Metrics
- CVSS 3.1
-
7.8
HIGH
Score source: CNA
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H - CVSS 4.0
-
8.5
HIGH
Score source: CNA
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - EPSS — exploit probability
- 0% percentile: 5 · as of 8 November 2026
- CWE
- CWE-121
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.