Is CVE-2026-39904 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-39904 being exploited in the wild.

How severe is CVE-2026-39904?

Medium severity, with a CVSS score of 6.5, published 22 June 2026.

Which products and versions are affected?

github.com/gophish/gophish (Go) <= 0.12.1, SEMVER:introduced=0, SEMVER:introduced=0,last_affected=0.12.1; Gophish <= 0.12.1, through 0.12.1.

Is there a fix for CVE-2026-39904?

No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

How is CVE-2026-39904 attacked?

It is attacked over the network, in a network appliance.

Am I affected by CVE-2026-39904?

Check whether you run github.com/gophish/gophish (Go) or Gophish at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-39904: Gophish denial of service via Office document upload in ApplyTemplate

Q: Is there a fix for CVE-2026-39904?

No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

Q: How is CVE-2026-39904 attacked?

It is attacked over the network, in a network appliance.

Q: Am I affected by CVE-2026-39904?

Check whether you run github.com/gophish/gophish (Go) or Gophish at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-39904 · Severity: medium · CVSS 6.5 · Published 2026-06-22

Gophish, an open-source phishing simulation platform, is vulnerable to a denial-of-service attack. An authorized user can crash the server by uploading a specially crafted Office document as an email template. This results in the server running out of memory and shutting down, disrupting ongoing security training and phishing simulations.

Technologies: github.com/gophish/gophish (Go). Vendors: Go.

Quick answers

Is CVE-2026-39904 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-39904 being exploited in the wild.
How severe is CVE-2026-39904?: Medium severity, with a CVSS score of 6.5, published 22 June 2026.
Which products and versions are affected?: github.com/gophish/gophish (Go) <= 0.12.1, SEMVER:introduced=0, SEMVER:introduced=0,last_affected=0.12.1; Gophish <= 0.12.1, through 0.12.1.
Is there a fix for CVE-2026-39904?: No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
How is CVE-2026-39904 attacked?: It is attacked over the network, in a network appliance.
Am I affected by CVE-2026-39904?: Check whether you run github.com/gophish/gophish (Go) or Gophish at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

A denial of service (DoS) vulnerability exists in Gophish versions up to and including 0.12.1 due to improper resource management in the ApplyTemplate() function within models/attachment.go. The application processes uploaded Office documents as ZIP archives but fails to enforce size limits on the uncompressed content. By calling ioutil.ReadAll() on entries within a crafted 'zip bomb' document, an authenticated attacker with standard User privileges can trigger unbounded memory allocation. This leads to system memory exhaustion and subsequent process termination by the operating system OOM killer. As of the advisory date, no official patch has been released.

Affected products

Gophish Gophish <= 0.12.1

Identifiers

CVE-2026-39904
GHSA-42jc-v69j-g38f
GO-2026-6212

Timeline

2026-06-22: disclosed
2026-06-22: advisory

References

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