Vaultwarden: Icon endpoint SSRF fix bypass via second-stage favicon IP literal URLs
- Published
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- Fix
- Fixed in 1.37.0
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
- Exploitation: poc
- Automatable: yes
- Technical impact: partial
Summary
Vaultwarden, a Bitwarden-compatible password manager server written in Rust, is affected in instances that have internal icon downloading enabled. A remote, unauthenticated attacker can abuse a flaw in favicon fetching to make the server reach loopback, private, or internal addresses, potentially exposing internal responses or revealing which internal services are reachable.
Summarized by anthropic/claude-haiku-5.5. Verify details against the original sources.
Read the original description
Vaultwarden is a Bitwarden-compatible server written in Rust. Prior to version 1.37.0, the Vaultwarden icon downloader validates the initial icon host and DNS results but passes favicon URLs parsed from attacker-controlled HTML to get_page_with_referer() without applying should_block_host() to the second-stage host. This flaw bypasses the remediation for CVE-2026-47160, which covered decimal, hexadecimal, octal, and IPv4-mapped IPv6 host normalization, because the second-stage IP-literal favicon fetch does not invoke the custom DNS resolver. A remote unauthenticated attacker can provide a public page whose favicon uses an IP-literal URL, allowing the Vaultwarden server to reach loopback or private and internal addresses. The issue affects instances with internal icon downloading enabled and can expose internal responses that resemble supported images or reveal reachability through timing, status, and cache behavior. This issue is fixed in version 1.37.0.
Timeline
- CVE published
- First seen by cve.now
- CISA SSVC assessment
Exploitation: poc · Automatable: yes · Technical impact: partial
- Record last updated
Affected versions
- dani-garcia vaultwarden
fixed in 1.37.0