CVE-2026-101878

HIGHPre-NVD 7.57.5—
EchelonGraph scoreHIGH confidence

Score 7.5 from GitHub Security Advisory (severity: HIGH) published 2026-09-29. The CNA's CVSS baseline 7.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cna:vulncheck, epss, ghsa
Trending — 4 sources updated this weekElevated
7.5EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.3%CVSS: 7.5Exploit: Elevated riskExposed services: Not assessed

A fix is available — apply it.

Bitwarden Server 2025.6.0 before 2026.5.0 declares the @ExternalId parameter of the User_ReadBySsoUserOrganizationIdExternalId stored procedure as NVARCHAR(50) while the column it queries stores NVARCHAR(300), silently truncating the SSO login identifier on SQL Server deployments and allowing a user whose identity-provider identifier begins with another organization member's full 50-character identifier to authenticate as that member and obtain a victim-scoped access token.

CVSS v3
7.5
EG Score
7.5HIGHhigh confidence
EG Risk
50
EG Risk 50/100CISA SSVC

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity75% × 45%
Exploitation40% × 40%
Automatability0% × 15%
CISA SSVC: Track at low, Track* at medium and Attend at high mission impact.
Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
EPSS PROB
0.3%
EPSS %ILE
15th
KEV
Not listed

CISA SSVCTrack at low, Track* at medium and Attend at high mission impact.

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation public PoC (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

September 29, 2026

Last Modified

October 1, 2026

Advisory Details (5)

Auto-updated Sep 29, 2026
Patch available. Sources: github_commit, github_pr, github_release.
generic

Bitwarden Server 2025.6.0 < 2025.6.0 Authentication Bypass via SSO Identifier Truncation | Advisories | VulnCheck

https://www.vulncheck.com/advisories/bitwarden-server-authentication-bypass-via-sso-identifier-truncation
generic

Sanjok Karki | Offensive Security Engineer

https://sanjokkarki.com.np/blog/bitwarden-sso-externalid-truncation
github_release Patch Available

Version 2026.5.0

Patch available: bitwarden/server v2026.5.0

https://github.com/bitwarden/server/releases/tag/v2026.5.0
github_pr

[PM-35252]

Fix merged in bitwarden/server PR #7501 on 2026-04-29 — awaiting tagged release

https://github.com/bitwarden/server/pull/7501
github_commit

commit 27ae3d5455f7 (bitwarden/server)

Fix landed in bitwarden/server commit 27ae3d5455f7 — awaiting tagged release

https://github.com/bitwarden/server/commit/27ae3d5455f723975fac03819eaeba8710666bc4

Vendor Advisories for CVE-2026-101878(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 32× in last 7d / 32× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-10-05 05:26 UTCEG score recompute
  2. 2026-10-05 05:26 UTCGHSA enrichment
  3. 2026-10-04 23:21 UTCEPSS rescore
  4. 2026-10-04 17:44 UTCGHSA enrichment
  5. 2026-10-04 06:01 UTCGHSA enrichment
  6. 2026-10-03 18:19 UTCEG score recompute
  7. 2026-10-03 18:19 UTCGHSA enrichment
  8. 2026-10-03 14:25 UTCEPSS rescore
  9. 2026-10-03 06:36 UTCGHSA enrichment
  10. 2026-10-02 18:54 UTCEG score recompute
  11. 2026-10-02 18:54 UTCGHSA enrichment
  12. 2026-10-02 07:12 UTCEG score recompute
  13. 2026-10-02 07:12 UTCGHSA enrichment
  14. 2026-10-01 19:49 UTCEPSS rescore
  15. 2026-10-01 19:31 UTCEG score recompute
  16. 2026-10-01 19:31 UTCGHSA enrichment
  17. 2026-10-01 17:00 UTCGHSA enrichment
  18. 2026-10-01 05:08 UTCGHSA enrichment
  19. 2026-09-30 17:26 UTCEG score recompute
  20. 2026-09-30 17:26 UTCGHSA enrichment
  21. 2026-09-30 15:02 UTCEPSS rescore
  22. 2026-09-30 06:13 UTCGHSA enrichment
  23. 2026-09-29 18:32 UTCEG score recompute
  24. 2026-09-29 18:31 UTCGHSA enrichment
  25. 2026-09-29 17:34 UTCEG score recompute
Show 7 more
  1. 2026-09-29 17:33 UTCGHSA enrichment
  2. 2026-09-29 15:20 UTCEPSS rescore
  3. 2026-09-29 14:10 UTCEG score recompute
  4. 2026-09-29 14:10 UTCGHSA enrichment
  5. 2026-09-29 02:29 UTCEG score recompute
  6. 2026-09-29 02:06 UTCEG score recompute
  7. 2026-09-29 02:06 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-101878?
CVE-2026-101878 is a high vulnerability published on September 29, 2026. Bitwarden Server 2025.6.0 before 2026.5.0 declares the @ExternalId parameter of the User_ReadBySsoUserOrganizationIdExternalId stored procedure as NVARCHAR(50) while the column it queries stores NVARCHAR(300), silently truncating the SSO login identifier on SQL Server deployments and allowing a…
When was CVE-2026-101878 disclosed?
CVE-2026-101878 was first published on September 29, 2026, with the most recent update on October 1, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-101878 actively exploited?
CVE-2026-101878 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.3% probability of exploitation in the next 30 days (15th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-101878?
CVE-2026-101878 has a CVSS base score of 7.5 (the CNA's own assessment, by vulncheck; NVD's own analysis pending).
How do I remediate CVE-2026-101878?
A fix for CVE-2026-101878 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-101878 are linked in the Vendor Advisories panel on this page.

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