How severe is CVE-2026-28280?

CVE-2026-28280 has a CVSS score of 6.1/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2026-28280?

CVE-2026-28280 affects the following packages: github.com/jmpsec/osctrl (Go). Ecosystems affected: Go.

How do I fix CVE-2026-28280?

Update github.com/jmpsec/osctrl to 0.5.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-28280 is resolved across your whole dependency graph.

How do I detect CVE-2026-28280 in my Go dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/jmpsec/osctrl, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2026-28280 if there is no patch (or I can't update yet)?

Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Is CVE-2026-28280 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-28280 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-28280?

CVE-2026-28280 has an EPSS (Exploit Prediction Scoring System) score of 0.3%, placing it in the 19th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-28280?

CVE-2026-28280 is classified as Cross-site Scripting (XSS) (CWE-79). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2026-28280 published, and has it been updated?

CVE-2026-28280 was published on February 26, 2026 and was last updated on October 28, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐹

🐹 Go

Not in CISA KEV

MEDIUM severity

CVE-2026-28280 — osctrl

MEDIUMFix: jmpsec/osctrl#778

CVE-2026-28280 is a medium-severity (CVSS 6.1) Cross-site Scripting (XSS) vulnerability in github.com/jmpsec/osctrl. A fix is available for github.com/jmpsec/osctrl — see the affected versions and patch details below.

`osctrl-admin` has Stored Cross-Site Scripting (XSS) in On-Demand Query List

Also known asGHSA-4rv8-5cmm-2r22GO-2026-4576

Published

Feb 26, 2026

Updated

Oct 28, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Nov 10, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

A successful exploit gives an attacker total control of the affected component, not partial access.
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-2026-28280.

EPSS Exploitation Probability

via FIRST.org ↗

0.3%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs19th percentile — riskier than 19% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

1 pkg affected

🐹github.com/jmpsec/osctrl

Real-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

Summary

A stored Cross-site Scripting (XSS) vulnerability exists in the osctrl-admin on-demand query list. A user with query-level permissions can inject arbitrary JavaScript via the query parameter when running an on-demand query. The payload is stored and executes in the browser of any user (including administrators) who visits the query list page. This can be chained with CSRF token extraction to escalate privileges and take actions as the logged in user.

Impact

An attacker with query-level permissions (the lowest privilege tier) can execute arbitrary JavaScript in the browsers of all users who view the query list. Depending on their level of access, it can lead to full platform compromise if an administrator executes the payload.

Patches

Fixed in osctrl v0.5.0. Users should upgrade immediately.

Workarounds

Restrict query-level permissions to trusted users. Monitor query list for suspicious payloads. Review osctrl user accounts for unauthorized administrators.

References

Credits

Leon Johnson and Kwangyun Keum from TikTok USDS JV Offensive Security Operations (Offensive Privacy Team)

https://github.com/Kwangyun → @Kwangyun

https://github.com/sho-luv → @sho-luv

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐹Go	`github.com/jmpsec/osctrl`	all versions	0.5.0`go get github.com/jmpsec/osctrl@v0.5.0`

Affected Products

1 product · 1 configurations

Application

osctrljmpsec

< 0.5.0

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/jmpsec/osctrl, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/jmpsec/osctrl to 0.5.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-28280 is resolved across your whole dependency graph.
Workarounds
Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Frequently Asked Questions

### Summary A stored Cross-site Scripting (XSS) vulnerability exists in the `osctrl-admin` on-demand query list. A user with query-level permissions can inject arbitrary JavaScript via the query parameter when running an on-demand query. The payload is stored and executes in the browser of any user (including administrators) who visits the query list page. This can be chained with CSRF token extraction to escalate privileges and take actions as the logged in user. ### Impact An attacker with query-level permissions (the lowest privilege tier) can execute arbitrary JavaScript in the browsers o