CVE-2026-31835: Vaultwarden is a Bitwarden-compatible server written in Rust

Q: How do I fix CVE-2026-31835?

vaultwarden: upgrade to 1.35.5. Exact commands for each OS are on this page.

Q: Is CVE-2026-31835 being exploited?

CVE-2026-31835 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-31835 affect?

CVE-2026-31835 affects vaultwarden. Severity is medium (CVSS 5.4). 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

Q: How urgent is CVE-2026-31835?

Priority 25/100. Public exploit reference

Routine

MEDIUM 5.4UPGRADE

CVE-2026-31835 is a medium-severity flaw (CVSS 5.4) affecting vaultwarden. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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

Why this priority

Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score	5.4 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.2% (top 96%)
CISA exploited list	No
Weakness	CWE-345
Published	2026-05-05
Last modified	2026-07-25

Publisher (CNA): GitHub, Inc. · Vendor: dani-garcia

Last updated 2026-07-25 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-05-05 19:16 UTCPublished CVE record published
2026-07-25 11:10 UTCUpdated Record last modified

dani-garcia vaultwarden UPGRADE

Affected: < 1.35.5

Fixed in: 1.35.5

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy vaultwarden || rpm -q vaultwarden || vaultwarden --version

2. UPGRADE to 1.35.5 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade vaultwarden

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade vaultwarden

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-31835?

vaultwarden: upgrade to 1.35.5. Exact commands for each OS are on this page.

Is CVE-2026-31835 being exploited?

CVE-2026-31835 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-31835 affect?

CVE-2026-31835 affects vaultwarden. Severity is medium (CVSS 5.4). 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

How urgent is CVE-2026-31835?

Priority 25/100. Public exploit reference

Related CVEs

CVE-2026-43912 HIGH 8.7 UPGRADE Vaultwarden is a Bitwarden-compatible server written in Rust
CVE-2026-43914 HIGH 7.3 UPGRADE Vaultwarden is a Bitwarden-compatible server written in Rust
CVE-2026-43913 HIGH 8.1 UPGRADE Vaultwarden is a Bitwarden-compatible server written in Rust
CVE-2026-43911 MEDIUM 6.8 UPGRADE Vaultwarden is a Bitwarden-compatible server written in Rust
CVE-2026-33420 MEDIUM 5.3 UPGRADE Vaultwarden is a Bitwarden-compatible server written in Rust

References

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