What is the CVSS score of CVE-2026-59218?

CVE-2026-59218 has a CVSS 3.1 base score of 5.3 (Medium). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N. EPSS exploitation probability: 0.2%.

Is there a patch available for CVE-2026-59218?

Yes, a patch is available for CVE-2026-59218. Update the affected software to the latest version immediately.

Open WebUI CVE-2026-59218

EUVD-2026-42617 MEDIUM

Observable Timing Discrepancy (CWE-208)

2026-07-09 GitHub_M

GHSA-7rw5-9f7q-xj36

Information Disclosure Open Webui

5.3

CVSS 3.1 · Vendor: GitHub_M

Severity by source

Vendor (GitHub_M) PRIMARY

5.3 MEDIUM

AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

vuln.today AI

5.3 MEDIUM

Network-accessible endpoint with no auth or special setup; impact is limited to account existence disclosure, so C:L and I:N/A:N.

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

4.0 AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N

Primary rating from Vendor (GitHub_M).

CVSS VectorVendor: GitHub_M

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

Low

Integrity

None

Availability

None

Lifecycle Timeline

Patch available

Jul 09, 2026 - 18:01 EUVD

Analysis Generated

Jul 09, 2026 - 17:23 vuln.today

DescriptionCVE.org

Open WebUI is an extensible, feature-rich, and user-friendly self-hosted AI platform. Prior to 0.10.0, the /api/v1/auths/signin endpoint looked users up by email and only ran bcrypt password verification when a credential existed, making registered-account attempts measurably slower than missing-email attempts and allowing unauthenticated account enumeration. This issue is fixed in version 0.10.0.

AnalysisAI

Timing-based account enumeration in Open WebUI prior to 0.10.0 exposes whether any given email address is registered on a self-hosted AI instance. The /api/v1/auths/signin endpoint only invokes bcrypt password verification when a matching email record exists, making registered-account login attempts measurably slower than attempts against unregistered emails - a classic CWE-208 timing oracle. Unauthenticated remote attackers can exploit this discrepancy at scale to harvest valid account emails, which can then fuel credential stuffing or targeted phishing. No public exploit code or CISA KEV listing has been identified, and the vendor has released a fix in v0.10.0.

Technical ContextAI

CWE-208 (Observable Timing Discrepancy) arises when a code path performs an expensive cryptographic operation - here, bcrypt - only under one conditional branch, leaking information through measurable latency differences. Bcrypt is intentionally slow to resist brute-force attacks; when it is skipped entirely for non-existent emails, the response-time gap is large enough to distinguish the two cases statistically without needing cryptographic precision. The affected component is the REST endpoint /api/v1/auths/signin in Open WebUI (CPE: cpe:2.3:a:open-webui:open-webui:*:*:*:*:*:*:*:*), a self-hosted, extensible AI platform. The canonical fix is to perform a constant-time dummy bcrypt operation (or equivalent) on every request regardless of whether the email lookup succeeds, collapsing the observable timing difference.

RemediationAI

Upgrade to Open WebUI version 0.10.0 or later, which resolves the timing oracle by ensuring consistent execution time on the signin path regardless of whether the provided email matches a registered account. The patched release is at https://github.com/open-webui/open-webui/releases/tag/v0.10.0 and the fix commit is https://github.com/open-webui/open-webui/commit/993e74912199c66c522f08ec81abe31d76985e39. If an immediate upgrade is not feasible, deploy a rate-limiting layer (e.g., nginx limit_req or a WAF rule) in front of the /api/v1/auths/signin endpoint to increase the cost and time required for statistical timing enumeration - note this slows but does not eliminate the attack for a patient adversary. Restricting network access to the signin endpoint to known IP ranges is a stronger compensating control but may not be practical for public-facing instances. Neither workaround addresses the root cause.