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Vulnerabilities

CVE-2026-21859

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Full record read. Reported values and explicit gaps below come from the tracked record. Tracker data as of: .

Detection and validation

Mapped metadata availability only. These signals do not change priority.

  • Sigma

    Not mapped by tracked sources.

  • Atomic

    Not mapped by tracked sources.

  • Nuclei

    Mailpit < 1.28.3 - Server-Side Request Forgery. Check identifier: CVE-2026-21859.

    Open Nuclei metadata

  • Metasploit

    Not mapped by tracked sources.

What it is

Reported

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.

Source reported · Source: NVD · Source last published: · Source description excerpt; complete tracked detail loads below. · Source last updated: · Tracker data as of:

What is affected

Reported

axllent; mailpit. Product-level identification only; no affected-version conclusion is available from this field.

Source reported · Source: NVD · Source last published: · Source last updated: · Tracker data as of:

Urgency and basis

Reported

Act · 442.7

Tracker computed · Tracker decision tier from the evidence detailed below · Source last updated: · Tracker data as of:

Exploitation evidence

Reported

listed by a tracked exploitation catalog · VulnCheck KEV

Source reported · VulnCheck KEV added: · Source last updated: · Tracker data as of:

What to do

Reported

Apply remediations or mitigations per vendor instructions or discontinue use of the product if remediation or mitigations are unavailable.

Source remediation ↗

Source reported · Tracked source remediation field · Source last updated: · Tracker data as of:

Evidence detail

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Glossary

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