CVE-2026-54339 Glean: Server-Side Request Forgery (SSRF) with Full Response Disclosure via Malicious RSS Feed in /api/feeds/discover
Attackers can exploit a malicious RSS feed to force the server to request internal resources and disclose full responses, including cloud metadata tokens.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-54339?
CVE-2026-54339 is a high-severity server-side request forgery vulnerability in LeslieLeung glean, published on 17 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
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 feed_url to discover_feed(feed_url), creates a subscription through FeedService.create_subscription(), and enqueues fetch_feed_task. The background path calls fetch_feed(feed.url) and parse_feed(), which assigns each RSS item link to ParsedEntry.url. The task then passes ParsedEntry.url to fetch_and_extract_fulltext(parsed_entry.url) without network-level validation in backend/packages/rss/glean_rss/extractor.py and backend/apps/worker/glean_worker/tasks/feed_fetcher.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.
Weakness: CWE-918
Which versions are affected by CVE-2026-54339?
How do I fix CVE-2026-54339?
No fix has been published for CVE-2026-54339 yet. Limit exposure of the affected software until one is available.
Upgrade, and send outbound requests through an allow-list that blocks internal addresses. More about Server-side request forgery.
Is CVE-2026-54339 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-54339 exists.
Sources
Also known as GHSA-78qf-q8fg-jcpg.