CVE-2023-45666: stb_image is a single file MIT licensed library for processing images. It may look like `stbi__load_gif_main` doesn’t give guarantees about the conte...

Description

stb_image is a single file MIT licensed library for processing images. It may look like `stbi__load_gif_main` doesn’t give guarantees about the content of output value `*delays` upon failure. Although it sets `*delays` to zero at the beginning, it doesn’t do it in case the image is not recognized as GIF and a call to `stbi__load_gif_main_outofmem` only frees possibly allocated memory in `*delays` without resetting it to zero. Thus it would be fair to say the caller of `stbi__load_gif_main` is responsible to free the allocated memory in `*delays` only if `stbi__load_gif_main` returns a non null value. However at the same time the function may return null value, but fail to free the memory in `*delays` if internally `stbi__convert_format` is called and fails. Thus the issue may lead to a memory leak if the caller chooses to free `delays` only when `stbi__load_gif_main` didn’t fail or to a double-free if the `delays` is always freed

Metrics

CVSS 3.1

9.8/10

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

EPSS Probability

0.96%

57.0th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Nothings	Stb Image.H	2.28

References

Timeline

Published: Oct 21, 2023
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2023-45666?

stb_image is a single file MIT licensed library for processing images. It may look like `stbi__load_gif_main` doesn’t give guarantees about the content of output value `*delays` upon failure. Although it sets `*delays` to zero at the beginning, it doesn’t do it in case the image is not recognized as GIF and a call to `stbi__load_gif_main_outofmem` only frees possibly allocated memory in `*delays` without resetting it to zero. Thus it would be fair to say the caller of `stbi__load_gif_main` is responsible to free the allocated memory in `*delays` only if `stbi__load_gif_main` returns a non null value. However at the same time the function may return null value, but fail to free the memory in `*delays` if internally `stbi__convert_format` is called and fails. Thus the issue may lead to a memory leak if the caller chooses to free `delays` only when `stbi__load_gif_main` didn’t fail or to a double-free if the `delays` is always freed

How severe is CVE-2023-45666?

CVE-2023-45666 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 0.96% probability of exploitation in the next 30 days.

How do I fix CVE-2023-45666?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.