What is CVE-2026-33809?

CVE-2026-33809 is a medium-severity vulnerability in Golang Tiff, classified under Unrestricted Upload of File with Dangerous Type. CVSS score: 5.3/10. Published 2026-03-25.

How severe is CVE-2026-33809?

Medium severity. CVSS v3 base score is 5.3 out of 10.

Arbitrary file upload in Golang Tiff

CVE-2026-33809

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.

Vulnerability class: Unrestricted File Upload

Published 2026-03-25 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N.

EPSS exploit prediction

EPSS: 0.004 (30.3th percentile), scored 2026-09-28.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 30th percentile — 30.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.003 · newest: 0.004 · change: +0.001

Affected products

Golang Tiff
Golang.org/x/image Golang.org/x/image/tiff — versions 0

Weakness classification (CWE)

CWE-434 — Unrestricted Upload of File with Dangerous Type

References

go.dev/cl/757660 (Mailing List)
go.dev/issue/78267 (Issue Tracking)
pkg.go.dev/vuln/GO-2026-4815 (Vendor Advisory)

Frequently asked questions

What is CVE-2026-33809?: CVE-2026-33809 is a medium-severity vulnerability in Golang Tiff, classified under Unrestricted Upload of File with Dangerous Type. CVSS score: 5.3/10. Published 2026-03-25.
How severe is CVE-2026-33809?: Medium severity. CVSS v3 base score is 5.3 out of 10.