{"cve":"CVE-2026-42181","nvd":{"published":"2026-05-08T20:16:31.160","modified":"2026-10-26T18:10:00.173","status":"Deferred","description":"Lemmy is a link aggregator and forum for the fediverse. Prior to version 0.19.18, Lemmy fetches metadata for user-supplied post URLs and, under the default StoreLinkPreviews image mode, downloads the preview image through local pict-rs. While the top-level page URL is checked against internal IP ranges, the extracted og:image URL is not subject to the same restriction. As a result, an authenticated low-privileged user can submit an attacker-controlled public page whose Open Graph image points to an internal image endpoint. Lemmy will fetch that internal image server-side and store a local thumbnail that can then be served back to users. This issue has been patched in version 0.19.18.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N","score":6.5},"cwes":["CWE-918"],"references":["https://github.com/LemmyNet/lemmy/releases/tag/0.19.18","https://github.com/LemmyNet/lemmy/security/advisories/GHSA-h6hf-9846-xwrq","https://github.com/LemmyNet/lemmy/security/advisories/GHSA-h6hf-9846-xwrq"],"products":[],"source":"nvd","synced_at":"2026-10-26T18:27:13.530666824+00:00"},"epss":{"cve":"CVE-2026-42181","score":0.00209,"percentile":0.10878,"date":"2026-10-26"},"kev":null,"osv":[{"id":"GHSA-h6hf-9846-xwrq","url":"https://osv.dev/vulnerability/GHSA-h6hf-9846-xwrq","summary":"Lemmy has SSRF and internal image disclosure in post link metadata via unvalidated og:image","modified":"2026-05-13T13:52:25.356705Z","packages":[{"ecosystem":"crates.io","name":"lemmy_api_common","purl":"pkg:cargo/lemmy_api_common","ranges":["<0.19.18"],"fixed":["0.19.18"]}]}],"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."]}