CVE-2026-77866

Server-Side Request Forgery (SSRF) vulnerability in Slab safeurl allows an attacker who controls a validated URL to reach internal network destinations the library is configured to block. Only IPv4 addresses are matched against the reserved ranges and the blocklist. Every other address is treated as matching nothing, so a destination that is rejected in its IPv4 form is accepted when written as an IPv6 address, IPv6 entries in the blocklist never match, and a host that resolves to no IPv4 address is accepted regardless of where it points. Deployments that rely on the allowlist instead are unaffected, because there an unmatched address is rejected. This issue affects safeurl: from 0.1.0 onward.

CVSS

No CVSS.

References

Link	Resource
https://cna.erlef.org/cves/CVE-2026-77866.html
https://github.com/slab/safeurl-elixir/commit/feabbd0a13f83028ab24b71710526e9da9841f70
https://osv.dev/vulnerability/EEF-CVE-2026-77866

Configurations

No configuration.

History

No history.

Information

Published : 2026-09-15 16:17

Updated : 2026-09-16 20:38

NVD link : CVE-2026-77866

Mitre link : CVE-2026-77866

CVE.ORG link : CVE-2026-77866

JSON object : View

Products Affected

No product.

CWE

CWE-636

Not Failing Securely ('Failing Open')

CWE-918

Server-Side Request Forgery (SSRF)

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