OliveTin has unauthenticated DoS via concurrent map writes in OAuth2 state handling

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

7.5 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS

• CVE-2026-28789: 0.45% estimated exploitation activity in the next 30 days; percentile 39.38 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary An unauthenticated denial-of-service vulnerability exists in OliveTin’s OAuth2 login flow. Concurrent requests to /oauth/login can trigger unsynchronized access to a shared registeredStates map, causing a Go runtime panic (fatal error: concurrent map writes) and process termination. This allows remote attackers to crash the service when OAuth2 is enabled. Details The OAuth2 handler stores per-login state in a shared map without synchronization: - service/internal/auth/otoauth2/restapiauthoauth2.go:24 registeredStates map[string]oauth2State - Unlocked write in login handler: .../restapiauthoauth2.go:141 - Unlocked read in callback check: .../restapiauthoauth2.go:174 - Unlocked writes in callback flow: .../restapiauthoauth2.go:284-285 - Unlocked read in auth chain check: .../restapiauthoauth2.go:376 These paths are network reachable via publicly registered routes: Because Go HTTP handlers run concurrently, high parallel traffic to /oauth/login causes concurrent map access and…

Published by the source

2 Mar 2026, 21:41 UTC

Last modified by the source

5 Mar 2026, 22:49 UTC

Source last checked

26 Oct 2026, 15:15 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-45m3-398w-m2m9

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# Patch Next advisory brief: CVE-2026-28789

Advisory: OliveTin has unauthenticated DoS via concurrent map writes in OAuth2 state handling
IDs: CVE-2026-28789, GHSA-45m3-398w-m2m9
Record: https://patchnext.com/advisories/cve-2026-28789 (revision 1, source checked 26 Oct 2026, 15:15 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: github.com/OliveTin/OliveTin 0.0.0-20260301235225-f044d90d5525c. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/OliveTin/OliveTin: affected < 0.0.0-20260301235225-f044d90d5525c; fixed in 0.0.0-20260301235225-f044d90d5525c

## Suggested inspection (read-only)
- Go github.com/OliveTin/OliveTin: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on github.com/OliveTin/OliveTin.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-45m3-398w-m2m9 (GitHub-reviewed advisory GHSA-45m3-398w-m2m9 lists affected ranges: Go github.com/OliveTin/OliveTin >=0 <0.0.0-20260301235225-f044d90d5525c)

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