# imgproxy integer overflow in ICO loader

Source: https://junglewise.ai/threats/go-2026-6897-imgproxy-has-integer-overflow-in-imgproxy-ico-loader-that-dbf52154  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-11-05. Updated: 2026-11-07  
License: CC BY 4.0 with a link back

Severity: info · Published 2026-11-05

imgproxy is an image processing service that handles various image formats including ICO files. An integer overflow in the ICO loader allows an attacker to send a specially crafted image file that causes the service to crash or potentially execute arbitrary code due to heap memory corruption.

Technologies: [github.com/imgproxy/imgproxy (Go)](https://junglewise.ai/threats/technologies/github-com-imgproxy-imgproxy), [github.com/imgproxy/imgproxy/v2 (Go)](https://junglewise.ai/threats/technologies/github-com-imgproxy-imgproxy-v2), [github.com/imgproxy/imgproxy/v3 (Go)](https://junglewise.ai/threats/technologies/github-com-imgproxy-imgproxy-v3), [github.com/imgproxy/imgproxy/v4 (Go)](https://junglewise.ai/threats/technologies/github-com-imgproxy-imgproxy-v4), [Imgproxy](https://junglewise.ai/threats/technologies/imgproxy). Vendors: [Go](https://junglewise.ai/threats/vendors/go), [Imgproxy](https://junglewise.ai/threats/vendors/imgproxy).

## Quick answers

**Is This vulnerability exploited in the wild?** No. Junglewise Threat Intelligence has no report of This vulnerability being exploited in the wild.

**How severe is This vulnerability?** Informational severity, published 5 November 2026.

**Which products and versions are affected?** github.com/imgproxy/imgproxy (Go) SEMVER:introduced=0; github.com/imgproxy/imgproxy/v2 (Go) SEMVER:introduced=0; github.com/imgproxy/imgproxy/v3 (Go) SEMVER:introduced=0; github.com/imgproxy/imgproxy/v4 (Go) SEMVER:introduced=4.0.0,fixed=4.0.16; and 1 more.

**Is there a fix for This vulnerability?** Yes. github.com/imgproxy/imgproxy/v4 (Go): upgrade to 4.0.16 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is This vulnerability attacked?** It is attacked over the network.

**Am I affected?** Check whether you run github.com/imgproxy/imgproxy (Go), github.com/imgproxy/imgproxy/v2 (Go), github.com/imgproxy/imgproxy/v3 (Go) or one of the others listed at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- github.com/imgproxy/imgproxy/v4 (Go): upgrade to 4.0.16 or later

  ```sh
  go get github.com/imgproxy/imgproxy/v4@v4.0.16
  ```


## Technical details

An integer overflow in vips/icoload.c occurs when computing data_size + BMP_FILE_HEADER_LEN (14 bytes) for an attacker-controlled 32-bit data_size value. When data_size exceeds UINT32_MAX - 14, the addition wraps to a small value, causing VIPS_MALLOC to allocate insufficient heap memory. The subsequent write of ICO prefix and original-size data causes a heap buffer overflow. This is reachable over the network with no authentication or user interaction required.

## Affected products

- imgproxy imgproxy 4.0.0 to 4.0.15

## Identifiers

- GHSA-hff9-5pqw-6w9f
- GO-2026-6897

## Timeline

- 2026-10-06: disclosed
- 2026-11-05: patched

## References

- [https://github.com/imgproxy/imgproxy/security/advisories/GHSA-hff9-5pqw-6w9f](https://github.com/imgproxy/imgproxy/security/advisories/GHSA-hff9-5pqw-6w9f)
- [https://github.com/imgproxy/imgproxy/commit/a821b6a4cb07a1bf2bb9077431d1c1e734d79917](https://github.com/imgproxy/imgproxy/commit/a821b6a4cb07a1bf2bb9077431d1c1e734d79917)

## Related threats

- [imgproxy integer overflow in ICO loader](https://junglewise.ai/threats/cve-2026-123614-imgproxy-from-4-0-0-before-4-0-16-contains-an-integer-overflow)
- [imgproxy unbounded memory allocation in ICO loader](https://junglewise.ai/threats/go-2026-6898-imgproxy-has-unbounded-memory-allocation-in-ico-loader-a99ea6ff)
- [imgproxy out-of-bounds heap read/write in ICO loader BMP header](https://junglewise.ai/threats/go-2026-6895-imgproxy-has-out-of-bounds-heap-read-write-in-ico-loader-d8e85817)
- [imgproxy integer overflow in ICO loader](https://junglewise.ai/threats/imgproxy-has-integer-overflow-in-imgproxy-ico-loader-that-causes-denial-19f131eb)
- [imgproxy out-of-bounds write in ICO loader BMP header](https://junglewise.ai/threats/imgproxy-has-out-of-bounds-heap-read-write-in-ico-loader-bmp-header-c4e077cd)