Medium severity5.8OSV Advisory· Published Jan 8, 2026· Updated Jun 17, 2026
CVE-2026-21859
CVE-2026-21859
Description
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.
AI Insight
LLM-synthesized narrative grounded in this CVE's description and references.
Affected packages
Versions sourced from the GitHub Security Advisory.
| Package | Affected versions | Patched versions |
|---|---|---|
github.com/axllent/mailpitGo | < 1.28.1 | 1.28.1 |
Affected products
5- ghsa-coords3 versionspkg:golang/github.com/axllent/mailpitpkg:rpm/opensuse/govulncheck-vulndb&distro=openSUSE%20Leap%2015.6pkg:rpm/opensuse/govulncheck-vulndb&distro=openSUSE%20Leap%2016.0
< 1.28.1+ 2 more
- (no CPE)range: < 1.28.1
- (no CPE)range: < 0.0.20260114T191543-150000.1.137.1
- (no CPE)range: < 0.0.20260723T184607-160000.1.1
Patches
Vulnerability mechanics
References
5- github.com/axllent/mailpit/commit/3b9b470c093b3d20b7d751722c1c24f3eed2e19dnvdPatchWEB
- github.com/axllent/mailpit/security/advisories/GHSA-8v65-47jx-7mfrnvdExploitVendor AdvisoryWEB
- github.com/advisories/GHSA-8v65-47jx-7mfrghsaADVISORY
- nvd.nist.gov/vuln/detail/CVE-2026-21859ghsaADVISORY
- pkg.go.dev/vuln/GO-2026-4284ghsaWEB
News mentions
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