What is the CVSS score of CVE-2026-41687?

CVE-2026-41687 has a CVSS 3.1 base score of 4.3 (Medium). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N. EPSS exploitation probability: 0.0%.

Is there a patch available for CVE-2026-41687?

Yes, a patch is available for CVE-2026-41687. Update the affected software to the latest version immediately.

Wallos CVE-2026-41687

EUVD-2026-28383 MEDIUM

Server-Side Request Forgery (SSRF) (CWE-918)

2026-05-07 GitHub_M

SSRF PHP

4.3

CVSS 3.1 · GitHub Advisory

Severity by source

GitHub Advisory PRIMARY

4.3 MEDIUM

AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

Primary rating from GitHub Advisory · only source for this CVE.

CVSS VectorGitHub Advisory

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

Low

Integrity

None

Availability

None

Lifecycle Timeline

Patch available

May 07, 2026 - 16:02 EUVD

Source Code Evidence Fetched

May 07, 2026 - 15:01 vuln.today

Analysis Generated

May 07, 2026 - 15:01 vuln.today

CVE Published

May 07, 2026 - 13:48 nvd

MEDIUM 4.3

DescriptionGitHub Advisory

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.

AnalysisAI

Blind SSRF via CGNAT address bypass in Wallos prior to version 4.8.1 allows authenticated users to probe internal services on Carrier-Grade NAT networks (100.64.0.0/10) through logo/icon URL fetching in subscription and payment endpoints. The vulnerability stems from incomplete IP range validation that fails to block RFC 6598 CGNAT addresses, enabling reconnaissance of services in Tailscale, dual-stack carrier environments, and internal infrastructure. CVSS 4.3 reflects limited confidentiality impact with authentication requirement; actively fixed in 4.8.1.

Technical ContextAI

Wallos implements SSRF protection using PHP's FILTER_FLAG_NO_PRIV_RANGE and FILTER_FLAG_NO_RES_RANGE filters in endpoints/subscription/add.php and endpoints/payments/add.php. These filters block RFC 1918 private ranges (10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16) and reserved ranges, but exclude RFC 6598 Carrier-Grade NAT space (100.64.0.0/10). While includes/ssrf_helper.php defines is_cgnat_ip() to address this gap and is correctly used in notification endpoints, the subscription and payment logo/icon URL fetching functions perform their own inline validation that neglects the CGNAT range. This allows authenticated attackers to craft URLs targeting 100.64.0.0/10 addresses to reach services deployed in Tailscale networks, carrier-grade NAT environments, or other deployments using this address space. The root cause is CWE-918 (Server-Side Request Forgery), exacerbated by incomplete allowlist/blocklist logic across multiple code paths.

RemediationAI

Upgrade Wallos to version 4.8.1 or later immediately. The patched version incorporates CGNAT range validation (100.64.0.0/10) into the inline IP checks and unifies SSRF validation logic across subscription, payment, and notification endpoints. For installations that cannot upgrade immediately, implement network-layer controls: restrict outbound HTTP/HTTPS from Wallos containers/instances to block traffic destined for 100.64.0.0/10 and RFC 1918 ranges at the firewall or security group level. Alternatively, disable logo/icon URL fetching by patching endpoints/subscription/add.php and endpoints/payments/add.php to reject any external URL input for these fields, reducing attack surface to zero at the cost of removing dynamic logo functionality. Monitor server logs for requests to 100.64.0.0/10 ranges or unusual curl/HTTP client activity from the Wallos process as a temporary detection control. See GitHub advisory GHSA-4v59-hghw-7gc2 and commit e79f28be6be0435fbc93563fb3c0e62206b48e85 for technical implementation details.