CVE-2026-33812 Excessive memory allocation when decoding malicious SFNT in golang.org/x/image
Attackers can cause denial of service by triggering excessive memory allocation when the Go image library parses malicious SFNT font files.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-33812?
CVE-2026-33812 is a medium-severity denial of service vulnerability in golang.org/x/image/font/sfnt, published on 21 Apr 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Official description
Parsing a malicious font file can cause excessive memory allocation.
Weakness: CWE-770
Which versions are affected by CVE-2026-33812?
1 open source package ship an affected version, including golang.org/x/image. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
golang.org/x/image Go | All versions | 0.39.0 |
Products include Golang Image.
How do I fix CVE-2026-33812?
Upgrade golang.org/x/image to 0.39.0 or later.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-33812 being exploited?
There is no known exploitation of CVE-2026-33812 in the wild and no public exploit code.
Other vulnerabilities in golang.org/x/image/font/sfnt
Sources
Also known as CLEANSTART-2026-LM41855, DEBIAN-CVE-2026-33812, GO-2026-4962, MINI-459p-hj64-qjg3, MINI-68jc-m8q8-wm7w, MINI-6w4h-w5wp-3977 and 12 more.