2FAuth: SSRF guard misses IPv6 NAT64 prefixes, allowing image fetch to reach internal/metadata targets
- Exploited
- No known exploitation
- Fix
- Fixed in 8.0.0
- Who is exposed
- Not reported
Do first: Upgrade to a fixed version: 8.0.0.
- Last modified
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 8/100 · provisional
- 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
Summary
2FAuth, a web app for managing two-factor authentication accounts, is affected by a server-side request forgery flaw that lets an attacker make the server fetch internal or cloud metadata addresses through IPv6 NAT64 prefixes. An attacker with low-privilege login can reach this remotely, and the flaw can also be triggered by tricking a victim into importing a crafted URI or migration payload, which may let the attacker recover image-shaped responses from internal endpoints or probe them blindly.
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
Read the original description
2FAuth is a web app to manage Two-Factor Authentication (2FA) accounts and generate their security codes. From 6.1.0 until 8.0.0, App\Services\Traits\ValidatesUrls::isPublicIp() does not recognize the 64:ff9b::/96 and 64:ff9b:1::/48 NAT64 prefixes, so an otpauth URI image parameter can pass an IPv6 literal or DNS64-synthesized address whose embedded IPv4 target is private, link-local, loopback, or cloud metadata. In a deployment with image fetching enabled and a NAT64 translation path to the internal IPv4 target, an account holder can submit the crafted URI directly, or an external attacker can induce a victim to import a crafted URI or migration payload. IconService::buildFromRemoteImage() then issues an HTTP GET to the embedded target, allowing image-shaped responses to be recovered or other endpoints to be probed blindly. This issue is fixed in version 8.0.0.
cve.now Index
- Exploitation?/40Unknown. No CISA SSVC exploitation rating yet
- Exposure3/25Reachable over the network · Unknown: No advisory context yet
- Reach?/20Unknown. No tracked technology or package matched
- Severity4.9/10CVSS 4.9
- No patch0/5No signal
What would change the score
- Would score about 63 if added to CISA KEV
- Would score about 58 if CISA's SSVC rates exploitation active
- Would score about 27 if advisories confirm default setups are exposed
What to do
Upgrade to a fixed version: 8.0.0.
Timeline
- CVE published
- First seen by cve.now
Affected versions
- Bubka 2FAuth
From 6.1.0 · fixed in 8.0.0
Evidence 3
- Advisory
- Repository
- Repository
Corrections
None so far.
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Questions about CVE-2026-63441
Is CVE-2026-63441 being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data
Which versions are affected by CVE-2026-63441?
2FAuth: from 6.1.0 before 8.0.0.Source: cve.now feed data
How do I fix CVE-2026-63441?
Upgrade to a fixed version: 8.0.0.Source: cve.now feed data