CVE-2026-54339: Glean: Server-Side Request Forgery (SSRF) with Full Response Disclosure via Malicious RSS Feed in /api/feeds/discover
Glean is a self-hosted RSS reader and personal knowledge management tool. Prior to 0.2.6, POST /api/feeds/discover passes an attacker-supplied feedurl to discoverfeed(feedurl), creates a subscription through FeedService.createsubscription(), and enqueues fetchfeedtask. The background path calls fetchfeed(feed.url) and parsefeed(), which assigns each RSS item link to ParsedEntry.url. The task then passes ParsedEntry.url to fetchandextractfulltext(parsedentry.url) without network-level validation in backend/packages/rss/gleanrss/extractor.py and backend/apps/worker/gleanworker/tasks/feedfetcher.py. A malicious feed can therefore make the server request private, loopback, link-local, or cloud-metadata resources. The fetched response is stored in Entry.content and can be retrieved through GET /api/entries/{id}, producing non-blind server-side request forgery with full response disclosure. This can bypass network perimeters, probe internal services and ports, expose internal configuration or web content, and potentially disclose cloud metadata access tokens. This issue is fixed in version 0.2.6.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
Gleanto a version that resolves this vulnerability.Fixed in 0.2.6
Event History
Frequently Asked Questions
Who can exploit this issue?
An attacker needs privileges to submit a POST request to /api/feeds/discover with an attacker-controlled feed_url. They can use a malicious RSS feed whose item links point to internal, loopback, link-local, or cloud-metadata resources.
Can an attacker read the responses from internal requests?
Yes. The worker fetches RSS item links and stores fetched content in Entry.content; the response can then be retrieved through GET /api/entries/{id}. This makes the SSRF non-blind and allows full response disclosure.
What versions are affected and what is the fix?
Glean versions prior to 0.2.6 are affected. Upgrade to version 0.2.6, which fixes the issue.
What could an attacker access through this vulnerability?
The server may be used to reach private, loopback, link-local, and cloud-metadata endpoints that are otherwise inaccessible to the attacker. This may expose internal services, configuration or web content, and potentially cloud metadata access tokens.