{"cve":"CVE-2022-41952","nvd":{"published":"2022-11-22T16:15:10.960","modified":"2026-06-17T05:04:07.573","status":"Modified","description":"Synapse before 1.52.0 with URL preview functionality enabled will attempt to generate URL previews for media stream URLs without properly limiting connection time. Connections will only be terminated after `max_spider_size` (default: 10M) bytes have been downloaded, which can in some cases lead to long-lived connections towards the streaming media server (for instance, Icecast). This can cause excessive traffic and connections toward such servers if their stream URL is, for example, posted to a large room with many Synapse instances with URL preview enabled. Version 1.52.0 implements a timeout mechanism which will terminate URL preview connections after 30 seconds. Since generating URL previews for media streams is not supported and always fails, 1.53.0 additionally implements an allow list for content types for which Synapse will even attempt to generate a URL preview. Upgrade to 1.53.0 to fully resolve the issue. As a workaround, turn off URL preview functionality by setting `url_preview_enabled: false` in the Synapse configuration file.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","score":5.3},"cwes":["CWE-772","CWE-400"],"references":["https://github.com/matrix-org/synapse/pull/11784","https://github.com/matrix-org/synapse/pull/11936","https://github.com/matrix-org/synapse/releases/tag/v1.52.0","https://github.com/matrix-org/synapse/releases/tag/v1.53.0","https://github.com/matrix-org/synapse/security/advisories/GHSA-4822-jvwx-w47h"],"products":["matrix:synapse"],"source":"nvd","synced_at":"2026-10-19T21:37:28.463369388+00:00"},"epss":{"cve":"CVE-2022-41952","score":0.00937,"percentile":0.60869,"date":"2026-11-01"},"kev":null,"osv":[{"id":"GHSA-4822-jvwx-w47h","url":"https://osv.dev/vulnerability/GHSA-4822-jvwx-w47h","summary":"Uncontrolled Resource Consumption in Matrix Synapse","modified":"2026-07-06T08:11:11.571767582Z","packages":[{"ecosystem":"PyPI","name":"matrix-synapse","purl":"pkg:pypi/matrix-synapse","ranges":["<1.53.0"],"fixed":["1.53.0"]}]},{"id":"PYSEC-2026-663","url":"https://osv.dev/vulnerability/PYSEC-2026-663","summary":"Uncontrolled Resource Consumption in Matrix Synapse","modified":"2026-07-06T08:00:38.809523599Z","packages":[{"ecosystem":"PyPI","name":"matrix-synapse","purl":"pkg:pypi/matrix-synapse","ranges":["<1.53.0"],"fixed":["1.53.0"]}]}],"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."]}