{"cve":{"cve_id":"CVE-2026-48788","is_kev":false,"kev_date_added":null,"kev_vendor_project":null,"kev_product":null,"kev_vulnerability_name":null,"kev_short_description":null,"kev_required_action":null,"kev_due_date":null,"kev_known_ransomware":null,"kev_notes":null,"kev_cwes":null,"epss_score":0.00251,"epss_percentile":0.16122,"epss_as_of":"2026-06-23","description":"Remark42 is a self-hosted comment engine for blogs, articles, or any other place where readers can add comments. Versions 1.6.0 through 1.15.0 contain a Cross-Site Scripting (XSS) vulnerability exploitable through content-type spoofing. The Remark42 image proxy fetches an arbitrary remote URL and re-serves the response from Remark42's own origin. During the download phase, the proxy determines whether the resource is an image by inspecting only the Content-Type header advertised by the remote server, never examining the actual bytes; during the serving phase, it instead derives the response Content-Type by sniffing those bytes with http.DetectContentType. An attacker can exploit this inconsistency by hosting a URL that advertises Content-Type: image/png while returning an HTML/JavaScript body: the download check accepts it as an image, the serving path sniffs the body and emits Content-Type: text/html, and the browser renders the attacker-controlled HTML/JavaScript as a document within Remark42's origin. Exploitation requires no Remark42 account on the target instance; the attacker only needs to host the malicious upstream URL and deliver the proxy link to a victim by any means, such as email, direct message, or a link on another website. This issue has been fixed in version 1.16.0.","published_at":"2026-06-16T22:29:38.877000Z","last_modified_at":null,"cvss_v3_score":8.2,"cvss_v3_vector":"CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:L/A:N","cvss_v3_severity":"HIGH","cvss_v4_score":null,"cvss_v4_vector":null,"cvss_v4_severity":null,"ssvc_decision":null,"ssvc_exploitation":null,"ssvc_automatable":null,"ssvc_technical_impact":null,"cwes":["CWE-79","CWE-436"],"nvd_references":["https://github.com/umputun/remark42/security/advisories/GHSA-4c8j-mgm4-qqvp","https://github.com/umputun/remark42/commit/78d6de6bce1e961f023969da3ec8a00dd80c9ae8","https://github.com/umputun/remark42/releases/tag/v1.16.0"],"vuln_status":null,"trending_score":null,"is_trending":false,"has_trended":false,"trended_number_one":false,"trending_peak_score":null,"trending_peak_rank":null,"started_trending_at":null,"trended_number_one_at":null,"summary_generated":null,"summary_generated_at":null,"summary_model":null,"created_at":"2026-06-24T00:09:39.878444Z","updated_at":"2026-06-28T23:30:44.057552Z"},"effective_severity":"HIGH","badges":[],"impact_analysis":[],"cvss_v3_decoded":{"version":"3.0","metrics":[{"metric":"AV","name":"Attack Vector","value":"N","value_label":"Network"},{"metric":"AC","name":"Attack Complexity","value":"L","value_label":"Low"},{"metric":"PR","name":"Privileges Required","value":"N","value_label":"None"},{"metric":"UI","name":"User Interaction","value":"R","value_label":"Required"},{"metric":"S","name":"Scope","value":"C","value_label":"Changed"},{"metric":"C","name":"Confidentiality","value":"H","value_label":"High"},{"metric":"I","name":"Integrity","value":"L","value_label":"Low"},{"metric":"A","name":"Availability","value":"N","value_label":"None"}]},"cvss_v4_decoded":{"version":null,"metrics":[]},"affected":[{"vendor_slug":"umputun","vendor_name":"umputun","product_slug":"remark42","product_name":"remark42","version_start":">= 1.6.0, < 1.16.0","version_start_inclusive":true,"version_end":">= 1.6.0, < 1.16.0","version_end_inclusive":true,"cpe23_uri":"cve5:umputun:remark42:>= 1.6.0, < 1.16.0:>= 1.6.0, < 1.16.0"}],"exploit_refs":[],"news":[],"references":[{"url":"https://github.com/umputun/remark42/security/advisories/GHSA-4c8j-mgm4-qqvp","source_type":"VENDOR_ADVISORY","tags":["advisory"]},{"url":"https://github.com/umputun/remark42/commit/78d6de6bce1e961f023969da3ec8a00dd80c9ae8","source_type":"PATCH","tags":["patch"]},{"url":"https://github.com/umputun/remark42/releases/tag/v1.16.0","source_type":"PATCH","tags":["patch"]}],"timeline":[{"type":"published","at":"2026-06-16T22:29:38.877000Z","label":"CVE published","source":null},{"type":"cvss_changed","at":"2026-06-28T17:55:03.830140Z","label":"CVSS score revised","source":"cvelistv5"},{"type":"cvss_changed","at":"2026-06-28T17:55:03.830140Z","label":"CVSS score revised","source":"cvelistv5"},{"type":"cvss_changed","at":"2026-06-28T17:55:03.830140Z","label":"CVSS score revised","source":"cvelistv5"}]}