2FAuth: SSRF guard misses IPv6 NAT64 prefixes, allowing image fetch to reach internal/metadata targets

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-63441
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-11-06 21:17:10 UTC
Updated2026-11-12 22:18:51 UTC
Description2FAuth 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.

Risk And Classification

Primary CVSS: v4.0 4.9 MEDIUM from [email protected]

CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:N/SC:H/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:X

EPSS: 0.003100000 probability, percentile 0.240200000 (date 2026-11-08)

Problem Types: CWE-918 | CWE-918 CWE-918: Server-Side Request Forgery (SSRF)

VersionSourceTypeScoreSeverityVector
4.0[email protected]Secondary4.9MEDIUMCVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:N/SC:H/SI:N/SA:N/E:X/C...
4.0CNADECLARED4.9MEDIUMCVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:N/SC:H/SI:N/SA:N

CVSS v4.0 Breakdown

Attack Vector
Network
Attack Complexity
Low
Attack Requirements
Present
Privileges Required
Low
User Interaction
None
Confidentiality
None
Integrity
None
Availability
None
Sub Conf.
High
Sub Integrity
None
Sub Availability
None

CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:N/SC:H/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:X

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Bubka 2FAuth affected >= 6.1.0, < 8.0.0 Not specified

References

ReferenceSourceLinkTags
github.com/Bubka/2FAuth/commit/df19e7533082671ecc2e0c735adcd51e93b1cb4c [email protected] github.com
github.com/Bubka/2FAuth/releases/tag/v8.0.0 [email protected] github.com
github.com/Bubka/2FAuth/security/advisories/GHSA-wc8m-7c5g-xrrc [email protected] github.com
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