Mailpit is vulnerable to Cross-Site WebSocket Hijacking (CSWSH) allowing unauthenticated access to emails
Mailpit is an email testing tool and API for developers. Prior to version 1.28.2, the Mailpit WebSocket server is configured to accept connections from any origin. This lack of Origin header validation introduces a Cross-Site WebSocket Hijacking (CSWSH) vulnerability. An attacker can host a malicious website that, when visited by a developer running Mailpit locally, establishes a WebSocket connection to the victim's Mailpit instance (default ws://localhost:8025). This allows the attacker to intercept sensitive data such as email contents, headers, and server statistics in real-time. This issue has been patched in version 1.28.2.
- Products
- Not specified
- Affected versions
- Not specified
- Fixed versions
- Not specified
- CVEs
- CVE-2026-22689
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 4 Nov 2026, 01:06 UTC · Revision 1
Source evidence
Mailpit is vulnerable to Cross-Site WebSocket Hijacking (CSWSH) allowing unauthenticated access to emails
core-osv · Original sourcePublished 10 Jan 2026, 05:46 UTC
Mailpit is an email testing tool and API for developers. Prior to version 1.28.2, the Mailpit WebSocket server is configured to accept connections from any origin. This lack of Origin header validation introduces a Cross-Site WebSocket Hijacking (CSWSH) vulnerability. An attacker can host a malicious website that, when visited by a developer running Mailpit locally, establishes a WebSocket connection to the victim's Mailpit instance (default ws://localhost:8025). This allows the attacker to intercept sensitive data such as email contents, headers, and server statistics in real-time. This issue has been patched in version 1.28.2.
osv:CVE-2026-22689
Complete source record
{
"id": "78ed33ee2b1fcce8157f98167693fa46efc1083e389ab00c86957b716d1338f4",
"url": "https://osv.dev/vulnerability/CVE-2026-22689",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "Mailpit is vulnerable to Cross-Site WebSocket Hijacking (CSWSH) allowing unauthenticated access to emails",
"summary": "Mailpit is an email testing tool and API for developers. Prior to version 1.28.2, the Mailpit WebSocket server is configured to accept connections from any origin. This lack of Origin header validation introduces a Cross-Site WebSocket Hijacking (CSWSH) vulnerability. An attacker can host a malicious website that, when visited by a developer running Mailpit locally, establishes a WebSocket connection to the victim's Mailpit instance (default ws://localhost:8025). This allows the attacker to intercept sensitive data such as email contents, headers, and server statistics in real-time. This issue has been patched in version 1.28.2.",
"evidence": "osv:CVE-2026-22689",
"products": [],
"severity": "medium",
"structured": {
"id": "CVE-2026-22689",
"aliases": [
"CVE-2026-22689",
"GHSA-524m-q5m7-79mm",
"GO-2026-4310"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N"
}
],
"affected": [
{
"ranges": [
{
"repo": "https://github.com/axllent/mailpit",
"type": "GIT",
"events": [
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{
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"source": "CPE_RANGE"
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{
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"source": "REFERENCES_COMMIT"
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"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-22689.json"
}
}
],
"modified": "2026-10-28T02:30:32.268616053Z",
"provider": "osv",
"references": [
"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/22xxx/CVE-2026-22689.json",
"https://github.com/axllent/mailpit/security/advisories/GHSA-524m-q5m7-79mm",
"https://nvd.nist.gov/vuln/detail/CVE-2026-22689",
"https://github.com/axllent/mailpit/commit/6f1f4f34c98989fd873261018fb73830b30aec3f"
],
"provider_metadata": {
"cwe_ids": [
"CWE-1385"
],
"cna_assigner": "GitHub_M",
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/22xxx/CVE-2026-22689.json"
}
},
"related_cves": [
{
"value": "CVE-2026-22689",
"evidence": "/id"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 499398,
"published_at": "2026-01-10T05:46:13.771+00:00"
}