Gophish contains a denial of service vulnerability (CVE-2026-39904)
Gophish versions up to 0.12.1 contain a denial of service vulnerability that allows authenticated users with the User role to exhaust server memory by uploading a specially crafted Office document as an email template attachment. The vulnerability arises because the ApplyTemplate() function processes Office documents as ZIP archives and reads all contained files without size restrictions, enabling a zip bomb payload to consume excessive memory and crash the process.
AI Analysis
Technical Summary
Gophish through version 0.12.1 is vulnerable to a denial of service attack via a crafted Office document uploaded as an email template attachment by an authenticated user with the User role. The ApplyTemplate() function in models/attachment.go treats Office documents as ZIP archives and calls ioutil.ReadAll() on each file entry without enforcing limits on the uncompressed size. This allows a zip bomb payload to expand to several gigabytes in memory, exhausting server resources and causing the process to be terminated by the operating system. The vulnerability is tracked as CVE-2026-39904 and is associated with CWE-770 (Allocation of Resources Without Limits or Throttling).
Potential Impact
An authenticated user with the User role can cause a denial of service by uploading a malicious Office document that triggers excessive memory consumption on the server. This results in the Gophish process being terminated by the operating system, disrupting service availability. There is no impact on confidentiality or integrity reported.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, restrict or monitor the ability of users with the User role to upload Office document attachments as email templates to prevent exploitation of this vulnerability.
Gophish contains a denial of service vulnerability (CVE-2026-39904)
Description
Gophish versions up to 0.12.1 contain a denial of service vulnerability that allows authenticated users with the User role to exhaust server memory by uploading a specially crafted Office document as an email template attachment. The vulnerability arises because the ApplyTemplate() function processes Office documents as ZIP archives and reads all contained files without size restrictions, enabling a zip bomb payload to consume excessive memory and crash the process.
CVSS v3.1
Score 6.5medium
Affected software
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Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
Gophish through version 0.12.1 is vulnerable to a denial of service attack via a crafted Office document uploaded as an email template attachment by an authenticated user with the User role. The ApplyTemplate() function in models/attachment.go treats Office documents as ZIP archives and calls ioutil.ReadAll() on each file entry without enforcing limits on the uncompressed size. This allows a zip bomb payload to expand to several gigabytes in memory, exhausting server resources and causing the process to be terminated by the operating system. The vulnerability is tracked as CVE-2026-39904 and is associated with CWE-770 (Allocation of Resources Without Limits or Throttling).
Potential Impact
An authenticated user with the User role can cause a denial of service by uploading a malicious Office document that triggers excessive memory consumption on the server. This results in the Gophish process being terminated by the operating system, disrupting service availability. There is no impact on confidentiality or integrity reported.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, restrict or monitor the ability of users with the User role to upload Office document attachments as email templates to prevent exploitation of this vulnerability.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- GHSA-42jc-v69j-g38f
- Osv Schema Version
- 1.4.0
- Aliases
- ["CVE-2026-39904"]
- Ecosystems
- ["Go"]
- Database Specific Severity
- HIGH
- Cvss Version
- 3.1
Threat ID: 6a75744cbf8831d539d9b016
Added to database: 08/07/2026, 05:59:40 UTC
Last enriched: 08/07/2026, 06:11:12 UTC
Last updated: 08/07/2026, 06:14:11 UTC
Views: 4
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