Junglewise Threat Intelligence

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

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

Technologies: golang.org/x/image (Go). Vendors: Go, Google, Go Project.

Executive brief

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.

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

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

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