Security readout for executives and security teams
Plain-English summary
Mailpit versions before 1.28.2 allowed any website to connect to its WebSocket interface. If a developer has Mailpit running locally and visits a malicious page, that page could read Mailpit email contents, headers, and server statistics in real time. This is mainly a developer-workstation confidentiality risk, not a general internet-wide server compromise.
Executive priority
Treat as a near-term developer security fix. The issue can expose sensitive emails used in testing, including account links, tokens, or customer-like data. It is not reported as actively exploited, but the patch is available and should be applied promptly across developer environments.
Technical view
CVE-2026-22689 is a Cross-Site WebSocket Hijacking issue caused by missing Origin header validation in Mailpit’s WebSocket server. The advisory describes default local access at ws://localhost:8025. The CVSS 3.1 score is 6.5 with high confidentiality impact, no integrity or availability impact, and required user interaction. Fixed in Mailpit 1.28.2.
Likely exposure
Organizations are exposed where developers or CI-like environments run Mailpit versions earlier than 1.28.2, especially on workstations used for web browsing. Exposure depends on a user visiting attacker-controlled web content while Mailpit is running and reachable from the browser context.
Exploitation context
The source bundle does not indicate active exploitation, and the CVE is not listed as KEV. Exploitation requires user interaction: a developer must browse to a malicious site while Mailpit is running. The main impact is unauthorized real-time access to test emails and related metadata.
Researcher notes
The key condition is missing Origin validation on the WebSocket server before 1.28.2. Validation should focus on version verification and whether local Mailpit instances are reachable from browser-originated WebSocket requests. Do not assume internet exposure unless deployment details confirm Mailpit is externally reachable.
Mitigation direction
- Upgrade Mailpit to version 1.28.2 or later.
- Review the GitHub advisory for vendor guidance.
- Identify and update developer environments using Mailpit before 1.28.2.
- Avoid browsing untrusted sites while vulnerable local Mailpit instances are running.
Validation and detection
- Inventory Mailpit installations and record versions.
- Confirm all installations are version 1.28.2 or later.
- Check developer workstation build files and containers for pinned vulnerable versions.
- Review whether sensitive test emails may have been exposed on vulnerable systems.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-1385: Exact CWE lookup
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Open ATT&CK lookupCVE-2026-22689 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Medium
- CVSS
- 6.5 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N2.83.6Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
6.5MediumVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/axllent/mailpit/security/advisories/GHSA-524m-q5m7-79mmCVE reference · x_refsource_CONFIRM
- https://github.com/axllent/mailpit/commit/6f1f4f34c98989fd873261018fb73830b30aec3fCVE reference · x_refsource_MISC
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Missing Origin Validation in WebSockets
Missing Origin Validation in WebSockets represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.