Is CVE-2026-43639 in the CISA KEV catalog?

No. CVE-2026-43639 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-43639?

CVE-2026-43639 has a CVSS v3 base score of 8.0 (HIGH).

What is the EPSS score for CVE-2026-43639?

CVE-2026-43639 has an EPSS score of 0.60% (44th percentile), estimating the probability of exploitation in the next 30 days.

CVE & CISA-KEV Catalog

CVE-2026-43639

HIGH

8.0

CVSS v3

NVD

Description

Bitwarden Server prior to v2026.4.0 contains a missing authorization vulnerability that allows a provider service user to add an arbitrary organization to their provider via `POST /providers/{providerId}/clients/existing`, resulting in takeover of the target organization; self-hosted installations are unaffected as this endpoint is restricted to Cloud via SelfHosted(NotSelfHostedOnly = true).

CWE-862Missing Authorization

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityHigh

Privileges RequiredHigh

User InteractionNone

ScopeChanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H

Exploit Intelligence

0.60%probability of exploitation in 30 days

44thpercentile

Moderate risk: more likely to be exploited than 44% of all known CVEs.

References

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-05-16.