CVE-2026-31835

mediumpriority · track · 22OT risk · elevatedEPSS 0.002 · 4 %ileDEEUUS

grimoire priorityP3 · Track

Exploitable?

—

no known exploitation

Likely / severe?

0.15% (4th) EPSS

CVSS 5.4 · medium

Is it mine?

4 products

Check your exposure

Who says so?

4 sources

cnnvd · enisa_euvd · cert_bund · nvd

EPSS · scored 2026-10-27

Vaultwarden is a Bitwarden-compatible server written in Rust. In versions 1.35.4 and earlier, the WebAuthn authentication flow in `validate_webauthn_login()` updates persistent credential metadata (1backup_eligible1 and 1backup_state flags1) based on unverified `authenticatorData` before signature validation is performed. An attacker who knows a user's password but cannot produce a valid WebAuthn signature can permanently modify the stored backup flags for that user's credential. If signature verification fails, the database update is not rolled back. This can result in a persistent denial of service of WebAuthn two-factor authentication for affected credentials. This issue has been fixed in version 1.35.5.

cvss

Technical severity, 0–10. One row per scoring source.

5.4

010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · low–medium · 1.3–5.4

v3.15.4mediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:Lprimary · NVD / NIST USexploitability 2.8 · impact 2.5

v4.05.3mediumCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:Nsecondary · ENISA EU

v4.05.3mediumCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/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:Xsecondary · security-advisories@github.com

v4.01.3lowCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U/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:Xsecondary · CVSS-BT (t0sche)

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Exploitation: poc · Automatable: no · Technical Impact: partialcoordinatorcisa_ssvcUS

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-345US

affected products (4)

Products and version ranges known to be affected.

Open Source Vaultwarden <1.35.5all versionscert_bundDE
Open Source Vaultwarden< 1.35.5cert_bundDE
dani-garcia vaultwarden≤ < 1.35.5enisa_euvdEU
dani-garcia vaultwarden< 1.35.5nvdUScpe:2.3:a:dani-garcia:vaultwarden:*:*:*:*:*:*:*:*

advisories (1)

Vendor and ecosystem advisories describing this.

WID-SEC-W-2026-1285Vaultwarden: Mehrere SchwachstellenDeutsch2026-04-26csaf · cert_bundDE
Ein Angreifer kann mehrere Schwachstellen in Vaultwarden ausnutzen, um Sicherheitsvorkehrungen zu umgehen, um einen Denial of Service Angriff durchzuführen, und um Informationen offenzulegen.

also known as (2)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd cert_bund nvd NVD CVE.org MITRE

published 2026-05-05modified 2026-07-25

references (5)

External citations — patches, advisories, analysis.

scry

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