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CVE-2026-41687

Wallos: SSRF CGNAT Bypass in subscription/payments Logo URL — is_cgnat_ip() Not Used in Inline Checks

MEDIUM
4.3
CVSS Score
Published: May 7, 2026 at 01:48 PM UTC
Updated: October 26, 2026 at 08:10 PM UTC
1 product affected across 1 vendorWallos

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Severity
MEDIUM4.3
Exploit prediction
EPSS 0.2%
SSVC
PoC

Description

Wallos is an open-source, self-hostable personal subscription tracker. Prior to version 4.8.1, the SSRF protection in endpoints/subscription/add.php (line 42) and endpoints/payments/add.php (line 40) uses an inline IP validation check (FILTER_FLAG_NO_PRIV_RANGE | FILTER_FLAG_NO_RES_RANGE) that does not block CGNAT addresses (100.64.0.0/10, RFC 6598). The includes/ssrf_helper.php file explicitly defines is_cgnat_ip() to cover this gap (used by notification endpoints), but the logo/icon URL fetching in subscription and payment endpoints performs its own inline validation that misses this range. This allows authenticated users to perform Blind SSRF to internal services in Tailscale, Carrier-Grade NAT, and other environments using 100.64.0.0/10 addresses. This issue has been patched in version 4.8.1.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Wallos· Ellite
90%
v < 4.8.1
Affected range stops below 4.8.1, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

References (3)

x_refsource_CONFIRM
Source: cverecord
https://github.com/ellite/Wallos/security/advisories/GHSA-4v59-hghw-7gc2
x_refsource_MISC
Source: cverecord
https://github.com/ellite/Wallos/commit/e79f28be6be0435fbc93563fb3c0e62206b48e85
x_refsource_MISC
Source: cverecord
https://github.com/ellite/Wallos/releases/tag/v4.8.1

SSVC — Action Prioritization

SSVCPoCNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

4.3MEDIUMGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
LOW
Integrity
NONE
Availability
NONE
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-918

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