CVE-2026-101878

Exploitation

Public exploit code exists. CISA's assessment records a public proof of concept. That is not a report of exploitation in the wild.

SSVC decision

• ExploitationpocPublic proof-of-concept exploit code exists. Not a report of exploitation in the wild.
• AutomatablenoAt least one step from reconnaissance to exploitation cannot be reliably automated.
• Technical ImpacttotalSuccessful exploitation gives total control of the vulnerable component.

CISA publishes the decision points, not a final SSVC decision. The decision also depends on mission and well-being impact, which is a property of your deployment rather than of the vulnerability.

EPSS probability

0.25% probability of exploitation activity in the next 30 days.

EPSS percentile

Equal to or higher than the score of 17.3% of scored records. A rank, not a probability.

NVD base score

7.7 (CVSS v4.0), scored by the NVD independently of the CNA.

NVD CVSS vector

CVSS:4.0/AV:N/AC:H/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

NVD analysis status

Awaiting Analysis. NVD last modified this record on 2026-09-30.

Red Hat severity

No Red Hat rating. Red Hat rates the CVEs that affect its products.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

Published

2026-09-29 01:58Z1 MO AGO

Last updated

2026-10-01 19:19Z27 DAYS AGO

Reserved

2026-09-28

Assigning CNA

VulnCheck

Record state

PUBLISHED

Severity

High (CVSS 7.7)

CNA CVSS vector

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

Weaknesses

• CWE-303Incorrect Implementation of Authentication AlgorithmBase

Data version

5.2

Document digest

842d8616fde5ff80e80343106c30689bcdf8dbdc1c7ec8a8c284b576c3eb1e80

• sanjokkarki.com.npResearcher Bloghttps://sanjokkarki.com.np/blog/bitwarden-sso-externalid-truncationtechnical-descriptionexploit
• github.comRelease Noteshttps://github.com/bitwarden/server/releases/tag/v2026.5.0release-notes
• github.comPull Requesthttps://github.com/bitwarden/server/pull/7501issue-tracking
• github.comPatch Commithttps://github.com/bitwarden/server/commit/27ae3d5455f723975fac03819eaeba8710666bc4patch
• www.vulncheck.comhttps://www.vulncheck.com/advisories/bitwarden-server-authentication-bypass-via-sso-identifier-truncationthird-party-advisory