5.4 Medium
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
REQUIRED
Scope
CHANGED
Confidentiality Impact
LOW
Integrity Impact
LOW
Availability Impact
NONE
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
5.9 Medium
AI Score
Confidence
High
4.9 Medium
CVSS2
Access Vector
NETWORK
Access Complexity
MEDIUM
Authentication
SINGLE
Confidentiality Impact
PARTIAL
Integrity Impact
PARTIAL
Availability Impact
NONE
AV:N/AC:M/Au:S/C:P/I:P/A:N
0.001 Low
EPSS
Percentile
40.8%
Miniflux is a feed reader. Since v2.0.25, Miniflux will automatically proxy images served over HTTP to prevent mixed content errors.
When an outbound request made by the Go HTTP client fails, the html.ServerError
is returned unescaped without the expected Content Security Policy header added to valid responses.
By creating an RSS feed item with the inline description containing an <img>
tag with a srcset
attribute pointing to an invalid URL like http:a<script>alert(1)</script>
, we can coerce the proxy handler into an error condition where the invalid URL is returned unescaped and in full.
This results in JavaScript execution on the Miniflux instance as soon as the user is convinced (e.g. by a message in the alt text) to open the broken image.
An attacker can execute arbitrary JavaScript in the context of a victim Miniflux user when they open a broken image in a crafted RSS feed. This can be used to perform actions on the Miniflux instance as that user and gain administrative access to the Miniflux instance if it is reachable and the victim is an administrator.
A patch is available in version 2.0.43. As a workaround sisable image proxy; default value is http-only
.
github.com/miniflux/v2/blob/b2fd84e0d376a3af6329b9bb2e772ce38a25c31c/ui/proxy.go#L76
github.com/miniflux/v2/blob/b2fd84e0d376a3af6329b9bb2e772ce38a25c31c/ui/proxy.go#L90
github.com/miniflux/v2/pull/1746
github.com/miniflux/v2/releases/tag/2.0.25
github.com/miniflux/v2/releases/tag/2.0.43
github.com/miniflux/v2/security/advisories/GHSA-mqqg-xjhj-wfgw
miniflux.app/docs/configuration.html#proxy-images
5.4 Medium
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
REQUIRED
Scope
CHANGED
Confidentiality Impact
LOW
Integrity Impact
LOW
Availability Impact
NONE
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
5.9 Medium
AI Score
Confidence
High
4.9 Medium
CVSS2
Access Vector
NETWORK
Access Complexity
MEDIUM
Authentication
SINGLE
Confidentiality Impact
PARTIAL
Integrity Impact
PARTIAL
Availability Impact
NONE
AV:N/AC:M/Au:S/C:P/I:P/A:N
0.001 Low
EPSS
Percentile
40.8%