Security readout for executives and security teams
Plain-English summary
Jellyfin servers before 10.7.3 could be abused without login to make the server fetch attacker-supplied URLs. This may expose HTTP resources that the Jellyfin server can reach, including internal web services not intended for public access.
Executive priority
Treat as a moderate-priority internet exposure issue. Patch or restrict affected Jellyfin servers promptly, especially if the server sits on a network with internal web services or cloud metadata-style HTTP resources.
Technical view
CVE-2021-29490 is an unauthenticated SSRF in Jellyfin remote image endpoints using the imageUrl parameter. Network attackers can trigger HTTP GET requests from the Jellyfin server. The vendor patched it in 10.7.3 and named reverse-proxy restrictions as a workaround.
Likely exposure
Exposure is limited to Jellyfin deployments running 10.7.2 or earlier. Risk is higher where Jellyfin is reachable from untrusted networks and can access internal HTTP services from its server environment.
Exploitation context
The source bundle does not indicate CISA KEV listing or confirmed active exploitation. The issue is remotely reachable, unauthenticated, low complexity, and limited to HTTP GET access visible from the Jellyfin server.
Researcher notes
This is CWE-918 SSRF with CVSS 3.1 score 5.8 and scope changed. The documented impact is confidentiality only. Sources do not support claims of code execution, write access, availability impact, or active exploitation.
Mitigation direction
- Upgrade Jellyfin to version 10.7.3 or later.
- Block unauthenticated external access to /Items/*/RemoteImages/Download via reverse proxy.
- Block or restrict /Items/RemoteSearch/Image to known-friendly IPs.
- Block or restrict /Images/Remote to known-friendly IPs.
- Review Jellyfin vendor advisory before applying compensating controls.
Validation and detection
- Confirm each Jellyfin server reports version 10.7.3 or later.
- Inventory internet-facing Jellyfin deployments and reverse proxy paths.
- Verify the three listed remote image endpoints are blocked or IP-restricted.
- Review access logs for unusual remote image URL requests.
- Confirm the server cannot reach sensitive internal HTTP resources unnecessarily.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-918: Information exposure and cloud metadata lookup
Information exposure and SSRF weaknesses can make discovery, cloud metadata, and credential material review relevant. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCloud metadata behavior lookup
The CVE wording references SSRF or metadata access, so cloud discovery and credential material review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2021-29490 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Medium
- CVSS
- 5.8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N3.91.4Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
5.8MediumVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/jellyfin/jellyfin/security/advisories/GHSA-rgjw-4fwc-9v96CVE reference · x_refsource_CONFIRM
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Server-Side Request Forgery (SSRF)
Server-Side Request Forgery (SSRF) represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.