OpenImageIO: TIFF 1-bit CMYK bit conversion heap out-of-bounds write

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

OpenImageIO is a toolset for reading, writing, and manipulating image files of any image file format relevant to VFX / animation. Prior to 3.1.16.0, A crafted 1-bit contiguous cmyk tiff is exposed through a native uint1 imagespec, so callers allocate a bit-packed buffer. tiffinput::read_native_scanline_locked() nevertheless invokes tiffinput::bit_convert() with 8-bit output and writes one expanded byte per value into that smaller buffer, resulting in a heap out-of-bounds write and memory corruption. The affected implementation is identified by src/tiff.imageio/tiffinput.cpp, TIFFInput::bit_convert(), TIFFInput::read_native_scanline_locked(), PHOTOMETRIC_SEPARATED, 1-bit CMYK, and native uint1 ImageSpec, which define the relevant source path, functions, state, and trigger. This issue is fixed in 3.1.16.0.

Source published

18 Sep 2026 15:49:38 UTC

Source modified

24 Sep 2026 20:57:37 UTC

Observed here

23 Oct 2026 15:48:27 UTC

Source terms

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CVSS 3.1 · 7.6 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:H