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Fencer Vulns
medium 5.3

CVE-2026-50167 json

Kurrier: Authenticated cross-user authorization bypass in Kurrier API

published 2026-08-18 2 mo ago modified 2026-10-22 17 d ago also EUVD-2026-61098

cvss
5.3
version 4.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 40%
public exploits
0
none known

Summary

Kurrier is a modern, self-hosted workspace for email, calendar, contacts, and storage. Prior to 1.2.4, Kurrier API endpoints for listing and retrieving webhook and identity resources did not enforce ownership checks for authenticated API requests. An attacker with a valid API key could use another account's identifiers to read and enumerate webhook and identity resources belonging to that account through apps/worker/server/routes/api/kurrier/webhooks/[id].get.ts, apps/worker/server/routes/api/kurrier/webhooks/index.get.ts, apps/worker/server/routes/api/kurrier/identities/[id].get.ts, and apps/worker/server/routes/api/kurrier/identities/index.get.ts. Anonymous requests and invalid API keys were rejected, and cross-user modification operations were blocked, but affected GET and list operations could expose another user's resource metadata. This issue is fixed in version 1.2.4.

Patch / fix

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
2 mo ago

Exploit prediction

0.46% chance of exploitation in the next 30 days, higher than 40% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 4.0 5.3 CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
CNA 4.0 5.3 CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected products

  • kurrier-org kurrier

Classification

Weakness
  • CWE-639 Authorization Bypass Through User-Controlled Key

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.