SixLabors ImageSharp CVE-2026-106114

The target application must decode attacker-supplied images with ImageSharp (versions 1.0.0-beta0001 through before 4.1.2) and reach ICC profile parsing. Two concrete paths exist: (1) the public IccProfile.Entries parsing path, which can allocate a large jagged representation from a truncated profile regardless of configuration; and (2) in version 4, the automatic image-conversion path through IccDataReader.ReadClutF32, which is ONLY reached when DecoderOptions.ColorProfileHandling is explicitly set to Convert - the default Preserve mode does NOT trigger this conversion and therefore avoids that path. The exploit requires crafting a short/truncated ICC profile that declares large CLUT channel and grid dimensions. Limiting factors: impact is bounded to memory pressure/input-validation failure (no confirmed process termination or RCE), and the v4 convert path depends on a non-default configuration setting, meaningfully narrowing exposure for default v4 deployments.

Signals are consistent and point to a genuine but modest (medium-severity) issue rather than an urgent priority. The vendor CVSS 3.1 vector (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L = 5.3) describes a remotely reachable, low-complexity, unauthenticated flaw whose ONLY impact is limited availability (memory pressure), with no confidentiality or integrity impact - matching CWE-789 (memory allocation with excessive size value) and the description's explicit statement that the demonstrated impact is 'memory pressure and input-validation failure, not unhandled process termination.' No EPSS score, KEV listing, or public POC was provided in the input; per precision rules this means no public exploit is identified at time of analysis and there is no evidence of active exploitation. A patched release (4.1.2) and the fixing commit/PR #3187 are available, which lowers residual risk for anyone who can upgrade. One nuance that tempers raw CVSS: in version 4 the vulnerable automatic-conversion path is only reached when DecoderOptions.ColorProfileHandling is set to the non-default Convert value - the default Preserve mode avoids it - so the practical attack surface for the v4 convert path is narrower than AV:N/PR:N alone suggests; however, the earlier IccProfile.Entries parsing paths can allocate a large jagged representation independent of that setting, so the network-reachable rating still holds. Note also that the input Tags label this 'Information Disclosure,' which conflicts with the CVSS vector (C:N) and the description - treat it as an availability/DoS-pressure issue, not data disclosure.

An attacker submits a specially crafted image containing a short, truncated ICC profile whose CLUT header declares very large channel and grid dimensions to an application that decodes untrusted images with ImageSharp (for example an avatar or upload-processing endpoint). The parser calculates and requests an oversized float/jagged array before validating that the profile actually contains the declared data, causing excessive memory allocation and degraded service. No public exploit is identified at time of analysis, though the fixing PR #3187 diff publicly illustrates the affected code paths.