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.
Attack Parameters
Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Privileges Required
None
No privileges needed
User Interaction
None
No user interaction needed
Impact Assessment
Confidentiality
None
No data leak
Integrity
None
No data modification
Availability
Low
Partial disruption
CVSS Vector v3.1
Weakness Type (CWE)
References 4
https://github.com/SixLabors/ImageSharp/commit/92b12d72550ebb6be5b1e22e559c361f…
security-advisories@github.com
https://github.com/SixLabors/ImageSharp/pull/3187
security-advisories@github.com
https://github.com/SixLabors/ImageSharp/releases/tag/v4.1.2
security-advisories@github.com
https://github.com/SixLabors/ImageSharp/security/advisories/GHSA-wmxv-xphr-5c9g
security-advisories@github.com