# CVE-2026-33813: Go x/image/webp denial of service on 32-bit platforms

Source: https://junglewise.ai/threats/cve-2026-33813-go-x-image-webp-denial-of-service-on-32-bit-platforms  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-04-21. Updated: 2026-06-25  
License: CC BY 4.0 with a link back

CVE-2026-33813 · Severity: high · CVSS 7.5 · Published 2026-04-21

A vulnerability in the Go programming language's WebP image processing library can cause applications to crash when processing specially crafted image files. This issue specifically affects systems running on 32-bit architectures. An attacker could exploit this to cause a denial-of-service, potentially disrupting business operations or services that allow users to upload or view images.

Technologies: [golang.org/x/image (Go)](https://junglewise.ai/threats/technologies/golang-org-x-image). Vendors: [Go](https://junglewise.ai/threats/vendors/go), [Google](https://junglewise.ai/threats/vendors/google).

## Quick answers

**Is CVE-2026-33813 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-33813 being exploited in the wild.

**How severe is CVE-2026-33813?** High severity, with a CVSS score of 7.5, published 21 April 2026.

**Which products and versions are affected?** golang.org/x/image (Go) SEMVER:introduced=0,fixed=0.42.0; Google Webp < 0.39.0.

**Is there a fix for CVE-2026-33813?** Yes. golang.org/x/image (Go): upgrade to 0.42.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-33813 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-33813?** Check whether you run golang.org/x/image (Go), image (Go) or Google Webp 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

- golang.org/x/image (Go): upgrade to 0.42.0 or later

  ```sh
  go get golang.org/x/image@v0.42.0
  ```


## Technical details

A denial-of-service vulnerability exists in the golang.org/x/image/webp package due to insufficient validation of canvas sizes in WebP VP8X headers. On 32-bit platforms, parsing a WebP image with a canvas size that overflows a 32-bit integer results in the creation of a corrupt image object. Subsequent access to this corrupt object triggers a runtime panic. The issue is reachable via the Decode and DecodeConfig functions. This vulnerability was addressed in version 0.42.0 of the golang.org/x/image library by implementing proper maximum size checks.

## Affected products

- Go Project golang.org/x/image/webp < 0.42.0

## Identifiers

- CVE-2026-33813
- GO-2026-4961

## Timeline

- 2026-03-27: disclosed: Issue reported to Go project by Tristan Madani
- 2026-04-21: advisory: CVE-2026-33813 published
- 2026-06-25: patched: Updated version 0.42.0 released

## References

- [https://pkg.go.dev/](https://pkg.go.dev/)
- [https://go.dev/cl/759860](https://go.dev/cl/759860)
- [https://go.dev/cl/780860](https://go.dev/cl/780860)
- [https://go.dev/issue/78407](https://go.dev/issue/78407)
- [https://pkg.go.dev/vuln/GO-2026-4961](https://pkg.go.dev/vuln/GO-2026-4961)

## Related threats

- [GO-2026-6222 - Excessive memory allocation during VP8L decoding in golang.org/x/image](https://junglewise.ai/threats/cve-2026-46603-go-2026-6222-excessive-memory-allocation-during-vp8l-decoding-in)
- [Go x/image/tiff denial of service via out-of-bounds strip offset](https://junglewise.ai/threats/cve-2026-46604-go-x-image-tiff-denial-of-service-via-out-of-bounds-strip-offset)
- [Go x/image/tiff unbounded memory consumption in TIFF decoder](https://junglewise.ai/threats/cve-2026-46602-go-x-image-tiff-unbounded-memory-consumption-in-tiff-decoder)
- [Go x/image/webp denial of service via mismatched VP8 dimensions](https://junglewise.ai/threats/cve-2026-46601-go-x-image-webp-denial-of-service-via-mismatched-vp8-dimensions)
- [Go x/image/tiff resource exhaustion in PackBits decompression](https://junglewise.ai/threats/cve-2026-46599-go-x-image-tiff-resource-exhaustion-in-packbits-decompression)