Medium
Mailpit Proxy Endpoint is Vulnerable to Server-Side Request Forgery (SSRF)
Type: advisorySources: OSV
Mailpit is an email testing tool and API for developers. Versions 1.28.0 and below have a Server-Side Request Forgery (SSRF) vulnerability in the /proxy endpoint, allowing attackers to make requests to internal network resources. The /proxy endpoint validates http:// and https:// schemes, but it does not block internal IP addresses, enabling attackers to access internal services and APIs. This vulnerability is limited to HTTP GET requests with minimal headers. The issue is fixed in version 1.28.1.
- Products
- Not specified
- Affected versions
- Not specified
- Fixed versions
- Not specified
- CVEs
- CVE-2026-21859
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 3 Nov 2026, 16:39 UTC · Revision 1
Source evidence
Mailpit Proxy Endpoint is Vulnerable to Server-Side Request Forgery (SSRF)
core-osv · Original sourcePublished 7 Jan 2026, 23:24 UTC
Mailpit is an email testing tool and API for developers. Versions 1.28.0 and below have a Server-Side Request Forgery (SSRF) vulnerability in the /proxy endpoint, allowing attackers to make requests to internal network resources. The /proxy endpoint validates http:// and https:// schemes, but it does not block internal IP addresses, enabling attackers to access internal services and APIs. This vulnerability is limited to HTTP GET requests with minimal headers. The issue is fixed in version 1.28.1.
osv:CVE-2026-21859
Complete source record
{
"id": "3d8006f0f17d8667ef975532bd600162b8f83733848287c9e6c79e9bf5177582",
"url": "https://osv.dev/vulnerability/CVE-2026-21859",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "Mailpit Proxy Endpoint is Vulnerable to Server-Side Request Forgery (SSRF)",
"summary": "Mailpit is an email testing tool and API for developers. Versions 1.28.0 and below have a Server-Side Request Forgery (SSRF) vulnerability in the /proxy endpoint, allowing attackers to make requests to internal network resources. The /proxy endpoint validates http:// and https:// schemes, but it does not block internal IP addresses, enabling attackers to access internal services and APIs. This vulnerability is limited to HTTP GET requests with minimal headers. The issue is fixed in version 1.28.1.",
"evidence": "osv:CVE-2026-21859",
"products": [],
"severity": "medium",
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"aliases": [
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"GHSA-8v65-47jx-7mfr",
"GO-2026-4284"
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"metrics": [
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"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N"
}
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"affected": [
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"type": "GIT",
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],
"modified": "2026-10-28T02:30:30.642320913Z",
"provider": "osv",
"references": [
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"https://github.com/axllent/mailpit/security/advisories/GHSA-8v65-47jx-7mfr",
"https://nvd.nist.gov/vuln/detail/CVE-2026-21859",
"https://github.com/axllent/mailpit/commit/3b9b470c093b3d20b7d751722c1c24f3eed2e19d"
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"provider_metadata": {
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}
},
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"evidence": "/id"
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"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 497498,
"published_at": "2026-01-07T23:24:07.869+00:00"
}