CVE-2026-33809 — x/image
MEDIUMCVE-2026-33809 is a medium-severity (CVSS 5.3) Unrestricted File Upload vulnerability in golang.org/x/image. A fix is available for golang.org/x/image — see the affected versions and patch details below.
Go Images vulnerable to an out-of-memory error via a crafted TIFF file
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-33809.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
golang.org/x/imageReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
Description
A maliciously crafted TIFF file can cause image decoding to attempt to allocate up 4GiB of memory, causing either excessive resource consumption or an out-of-memory error.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | golang.org/x/image | all versions | 0.38.0go get golang.org/x/image@v0.38.0 |
Affected Products
tiffgolangDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for golang.org/x/image, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update golang.org/x/image to 0.38.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-33809 is resolved across your whole dependency graph.
Workarounds
Treat uploaded files as untrusted until proven otherwise: validate the actual content type rather than the supplied extension, store uploads outside the web root on a volume mounted without execute permission, and rename them to server-generated identifiers so an attacker cannot choose the path a request will later resolve.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.Source: Red Hat security advisory for CVE-2026-33809 (CC BY 4.0)
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat Hardened Images | golang1-26-main-1.26.2-1.hum1 | RHSA-2026:7291 |
| Red Hat Hardened Images | golang1-25-main-1.25.9-1.hum1 | RHSA-2026:7385 |
Frequently Asked Questions
Is CVE-2026-33809 in your dependencies?
Find it across Go, including transitive dependencies.