CVE-2026-39904 Gophish 0.12.1 Denial of Service via Office Document Upload
Authenticated users can cause denial of service by uploading crafted Office documents that trigger memory exhaustion via zip bomb processing.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-39904?
CVE-2026-39904 is a high-severity denial of service vulnerability in gophish, published on 22 Jun 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
Gophish through 0.12.1 contains a denial of service vulnerability that allows authenticated users with the User role to exhaust server memory by uploading a crafted Office document as an email template attachment. The ApplyTemplate() function in models/attachment.go processes Office documents as ZIP archives and calls ioutil.ReadAll() on each contained file entry without enforcing size restrictions on uncompressed content, allowing a zip bomb payload to expand to several gigabytes in memory and cause the process to be terminated by the operating system.
Weakness: CWE-770
Which versions are affected by CVE-2026-39904?
3 open source packages ship an affected version, including github.com/gophish/gophish.
| Package | Affected | Fixed in |
|---|---|---|
github.com/gophish/gophish Go | All versions | None |
github.com/gophish/gophish Go | All versions to 0.12.1 | None |
github.com/gophish/gophish Go | All versions to 0.12.1 | None |
How do I fix CVE-2026-39904?
Upgrade to a fixed version.
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-2026-39904 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-39904 exists.
Sources
Also known as GHSA-42jc-v69j-g38f, GO-2026-6212.