ImageSharp is a 2D graphics library. From 2.0.0 until 4.1.2, ExifReader.ReadValues64 trusts the 64-bit BigTIFF IFD entry count and iterates once per declared entry. When fewer than 20 bytes remain, ExifReader.ReadValue64 returns without advancing the stream or terminating the outer loop, so a small malformed BigTIFF can keep one decoder thread executing for an attacker-controlled duration. This report does not claim worker-pool exhaustion. This issue is fixed in version 4.1.2.
Weakness
The product contains an iteration or loop with an exit condition that cannot be reached, i.e., an infinite loop.
References
- https://github.com/SixLabors/ImageSharp/commit/92b12d72550ebb6be5b1e22e559c361fd863a6ec
- https://github.com/SixLabors/ImageSharp/pull/3187
- https://github.com/SixLabors/ImageSharp/releases/tag/v4.1.2
- https://github.com/SixLabors/ImageSharp/security/advisories/GHSA-wmxv-xphr-5c9g
- https://github.com/SixLabors/ImageSharp/security/advisories/GHSA-wmxv-xphr-5c9g