{"cve":"CVE-2026-33693","nvd":{"published":"2026-03-27T01:16:18.983","modified":"2026-06-17T10:37:56.163","status":"Deferred","description":"Lemmy is a link aggregator and forum for the fediverse. Prior to version 0.7.0-beta.9, the `v4_is_invalid()` function in `activitypub-federation-rust` (`src/utils.rs`) does not check for `Ipv4Addr::UNSPECIFIED` (0.0.0.0). An unauthenticated attacker controlling a remote domain can point it to 0.0.0.0, bypass the SSRF protection introduced by the fix for CVE-2025-25194 (GHSA-7723-35v7-qcxw), and reach localhost services on the target server. Version 0.7.0-beta.9 patches the issue.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N","score":6.5},"cwes":["CWE-918"],"references":["https://github.com/LemmyNet/activitypub-federation-rust/commit/4ae8532b17bc35755240b7f55d4a5b7665351599","https://github.com/LemmyNet/lemmy/security/advisories/GHSA-q537-8fr5-cw35","https://github.com/advisories/GHSA-7723-35v7-qcxw"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:28:18.033120106+00:00"},"epss":{"cve":"CVE-2026-33693","score":0.00373,"percentile":0.31285,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-q537-8fr5-cw35","url":"https://osv.dev/vulnerability/GHSA-q537-8fr5-cw35","summary":"Activitypub-Federation has SSRF via 0.0.0.0 bypass in activitypub-federation-rust v4_is_invalid()","modified":"2026-04-02T13:44:32.200396077Z","packages":[{"ecosystem":"crates.io","name":"activitypub_federation","purl":"pkg:cargo/activitypub_federation","ranges":["<0.7.0-beta.9"],"fixed":["0.7.0-beta.9"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}