vulnerability / NVI-00015332 / Revision 2
Mailpit: WebSocket origin check bypass via percent-encoded path (regression of CVE-2026-22689)
GitHub lists this reviewed advisory for github.com/axllent/mailpit. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.
This report has not inspected your inventory, configuration, deployed build, reachability or evidence. A catalog listing and a severity score do not establish exposure or compromise.
01 / Meaning
Why it matters
Published affected context helps an owner decide what evidence to gather. This report has not examined your application.
6.5 medium
GitHub source severity; exploitability and local consequence require separate evidence.
As of · GitHub Advisory Database
0.221%
FIRST EPSS model v2026.06.15; exploitation probability over 30 days, percentile 0.12699. Missing scores are unknown.
As of · FIRST EPSS
02 / Applicability
The affected context
Affected versions, configuration prerequisites and known exclusions are public. Confirm each one against the deployed service.
github.com/axllent/mailpit
source listed>= 1.29.0, <= 1.30.5
## Summary The cross-site WebSocket hijacking fix was reimplemented as an origin check gated on a raw-URI prefix test, but Go's ServeMux routes on the percent-decoded path, so requesting /%61pi/events reaches the WebSocket handler while skipping the only origin control, and the upgrader itself accepts every origin. Confirmed at HEAD 408b30d. Affects 1.29.0 through 1.30.5. ## The defect Two halves that were each correct in isolation. server/websockets/client.go accepts any origin and delegates the check elsewhere: ```go var upgrader = websocket.Upgrader{ // line 33 ... CheckOrigin: func(_ *http.Request) bool { // line 37 // origin is checked via server.go's CORS settings return true // line 39 }, } ``` server/server.go performs that check but keys it on the RAW request target: ```go if strings.HasPrefix(r.RequestURI, config.Webroot+"api/") || htmlPreviewRouteRe.MatchString(r.RequestURI) { // line 320 if allowed := corsOriginAccessControl(r); !allowed { http.Error(w, "Blocked due to CORS violation", http.StatusForbidden) return } ``` r.RequestURI is the u
03 / Response
What to do next
- investigate
Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.
Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system. FIRST EPSS
A fixed release is not deployment evidence.
Check current vendor support and compatibility. After making a change, verify the deployed build and relevant runtime conditions. Keep the evidence, owner and time. An updated lockfile alone does not prove what is running.
04 / Limits
What this report cannot establish
- Customer inventory, deployment, reachability and exploitation have not been inspected.
05 / Provenance
Sources you can inspect
Each assertion retains its source. Mirrored records may repeat one underlying publisher; additional links are not independent corroboration.
- GHSA-8r62-w5wh-fc5m ↗
GitHub Advisory Database · vendor advisory
Observed . GitHub Advisory Database; CC-BY-4.0. Each advisory links its original attribution. Null normalizes fields.
- CVE-2026-67448 ↗
FIRST EPSS · official catalog
Observed . FIRST EPSS; probability of exploitation in the next 30 days, not local compromise. Dataset date/model retained; FIRST services terms apply.
Public revision history
Only published revisions appear here. Routine fetches do not create a material-change event.
- Revision 2 ·
Dated EPSS estimate updated; this is not a new disclosure or proof of exploitation.
- Revision 1 ·
First indexed by Null; source disclosure date is shown separately.