Open WebUI: Account enumeration via observable login timing discrepancy

Exploitation

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

CVSS

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

EPSS

• CVE-2026-59218: 0.41% estimated exploitation activity in the next 30 days; percentile 35.56 (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 The /api/v1/auths/signin endpoint leaked whether an email address belonged to a registered account through a response-time side channel. Password verification ran bcrypt only when the email was found in the database; for a non-existent email the request returned early without hashing. The expensive bcrypt comparison therefore made valid-account attempts respond significantly slower (~180 ms) than non-existent ones (~5 ms), so an unauthenticated attacker could enumerate valid accounts by measuring response time. Details On signin the backend looked the user up by email and only performed the bcrypt password comparison if a record existed. A missing email short-circuited before any hashing, producing the timing gap. The built-in brute-force throttling did not prevent it: sending one request at a time with a small delay between requests stays under the rate limit while still exposing the difference. Observed in the reporter's run (HTTP 400 for every attempt, the response time is…

Published by the source

24 Jul 2026, 16:55 UTC

Last modified by the source

4 Aug 2026, 14:41 UTC

Source last checked

26 Oct 2026, 13:49 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-7rw5-9f7q-xj36

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-7rw5-9f7q-xj36

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# Patch Next advisory brief: CVE-2026-59218

Advisory: Open WebUI: Account enumeration via observable login timing discrepancy
IDs: CVE-2026-59218, GHSA-7rw5-9f7q-xj36
Record: https://patchnext.com/advisories/cve-2026-59218 (revision 2, source checked 26 Oct 2026, 13:49 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: open-webui 0.10.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI open-webui: affected < 0.10.0; fixed in 0.10.0

## Suggested inspection (read-only)
- `python -m pip show open-webui`: prints the installed version. Run with the environment that serves production active.

## 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 open-webui.
- 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://osv.dev/vulnerability/GHSA-7rw5-9f7q-xj36 (OSV record GHSA-7rw5-9f7q-xj36 lists affected ranges: PyPI open-webui >=0 <0.10.0 (fixed))
- Verified: https://github.com/advisories/GHSA-7rw5-9f7q-xj36 (GitHub-reviewed advisory GHSA-7rw5-9f7q-xj36 lists affected ranges: PyPI open-webui >=0 <0.10.0)

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