CVE-2023-27592 is a medium-severity (CVSS 4.8) Cross-site Scripting (XSS) vulnerability in miniflux.app/v2. A fix is available for miniflux.app/v2 — see the affected versions and patch details below.
Stored XSS in Miniflux when opening a broken image due to unescaped ServerError in proxy handler
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2023-27592.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2023-27592 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,333 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
miniflux.app/v2Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
Description
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.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | miniflux.app/v2 | ≥ 2.0.25&&< 2.0.43 | 2.0.43go get miniflux.app/v2@v2.0.43 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for miniflux.app/v2, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update miniflux.app/v2 to 2.0.43 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-27592 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2023-27592 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2023-27592. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2023-27592 in your dependencies?
O3 Security finds CVE-2023-27592 across Go dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.