What is CVE-2026-71959?

CVE-2026-71959 is a medium-severity vulnerability in Bitwarden Server, classified under Missing Authorization. CVSS score: 5.8/10. Published 2026-08-10.

How severe is CVE-2026-71959?

Medium severity. CVSS v3 base score is 5.8 out of 10.

Auth bypass in Bitwarden Server

CVE-2026-71959

Bitwarden Server before 2026.7.2 does not verify that the caller is a member of the organization identified in a POST /collect request body, allowing any authenticated user to write forged, arbitrarily backdated entries into any organization's audit log.

Vulnerability class: Broken Access Control

Published 2026-08-10 · last modified 2026-08-17.

CVSS v3 metric

CVSS v3 base score 5.8 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N.

EPSS exploit prediction

EPSS: 0.003 (21.8th percentile), scored 2026-09-24.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 22nd percentile — 21.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: 0.000

Affected products

Bitwarden Server — versions 0

Weakness classification (CWE)

CWE-862 — Missing Authorization

References

github.com/bitwarden/server/commit/2aa92a3c8675a28e305e8207ff16592227f96291 (patch)
github.com/bitwarden/server/pull/7934 (issue-tracking)
github.com/bitwarden/server/releases/tag/v2026.7.2 (release-notes)
sanjokkarki.com.np/blog/bitwarden-audit-log-forgery (technical-description, exploit)
www.vulncheck.com/advisories/bitwarden-server-audit-log-injection-via-post-coll… (third-party-advisory)

Frequently asked questions

What is CVE-2026-71959?: CVE-2026-71959 is a medium-severity vulnerability in Bitwarden Server, classified under Missing Authorization. CVSS score: 5.8/10. Published 2026-08-10.
How severe is CVE-2026-71959?: Medium severity. CVSS v3 base score is 5.8 out of 10.