self-xss-escalation SKILL.md skillA
self-xss-escalation from dreadnode/capabilities is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.
mdr add dreadnode/capabilities/self-xss-escalation@git:20260529.17de87fPins git:20260529.17de87f in mdr.lock. Pin the fingerprint instead.
- Audit grade
- A, 17 of 17 checks passed
- Kind
- SKILL.md skill
- Repository
- dreadnode/capabilities
- Path
capabilities/web-security/skills/self-xss-escalation/SKILL.md- Versions recorded
- 1
- Latest version
- git:20260529.17de87f, committed May 29, 2026
- Size
- 3,709 bytes
- Repository stars
- 22
- License
- MIT
Escalate self-XSS to full-impact XSS via login CSRF, cookie bombing, path-specific cookie precedence, and double-XSS chains. Use when you have XSS that only fires in the attacker's own session.
Collected from public GitHub. Every version is saved exactly as it was and never changes. Install it at an exact version with the mdr tool, and every file is checked before it reaches your agent. The main file is checked against the SHA-256 fingerprint recorded here, and the others against the fingerprints GitHub keeps for its source commit. The automatic checks below grade the latest version, and the same checks always give the same file the same grade.
What the file says
# Self-XSS Escalation
You found XSS but it only triggers in your own authenticated session -- the payload is tied to your account data. This skill turns self-XSS into full account takeover.
## Technique 1: OAuth Login CSRF
Force the victim's browser into the attacker's session, where the XSS payload is waiting.
```
Step 1: Start OAuth flow for attacker account, capture authorization code
(Burp/Caido intercept the callback redirect)
Step 2: Force victim to consume the code:
<img src="https://target.com/auth/callback?code=ATTACKER_CODE&state=ATTACKER_STATE">
Step 3: Victim is now logged in as attacker; self-XSS payload fires
```
**State parameter bypass:**
- Check if `state` is tied to session or just a CSRF token
- If in a cookie, set it via cookie injection (XSS on subdomain, cookie tossing)
- Some apps only validate presence, not value
- Some apps skip validation entirely on the callback endpoint
**Token/code lifetime:** OAuth codes are typically single-use, expire in 60s-600s. Move fast.
## Technique 2: Cookie Bombing for Forced Logout
Set enough cookies to exceed the server's header size limit (typically 8KB-16KB), causing 431 errors.
```javascript
…Read the whole file at its exact version.
How to install
mdr add dreadnode/capabilities/self-xss-escalation@sha256:8cbca624d0b64b94The line at the top of this page pins the label git:20260529.17de87f, which is what most people want. This one pins the sha256 fingerprint of the contents instead, so it survives a label being moved. Either way the exact version is written to mdr.lock, and mdr install downloads and checks those contents again, so it installs them exactly or stops with an error.
[](https://markdownregistry.com/a/art_paa4rhl5j77sjl4m)
3 badge image fetches in 30 days. What the badge shows.
Versions
The registry has recorded 1 version of this file, committed on May 29, 2026.
Audit of the latest version
- pass: Frontmatter block present
- pass: Frontmatter declares a name
- pass: Frontmatter declares a description
- pass: Size between 200 bytes and 200 KB (3709 bytes)
- pass: No zero-width or bidi control characters
- pass: No instruction hidden inside an HTML comment
- pass: No link to an exfiltration or paste host
- pass: No credential-shaped string
- pass: No instruction to send local credentials anywhere
- pass: No text hidden with inline styles
- pass: No prompt-injection phrasing
- pass: No curl or wget piped into a shell
- pass: No recursive delete of root, home or parent
- pass: No instruction to read or print local credentials
- pass: No base64 blob over 200 characters
- pass: No link to a raw IP address
- pass: No script tag
Source
dreadnode/capabilities · 22 stars · license MIT · pushed 2026-11-02 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_paa4rhl5j77sjl4m GET https://markdownregistry.com/api/v1/resolve?ref=dreadnode/capabilities/self-xss-escalation GET https://markdownregistry.com/api/v1/blob/8cbca624d0b64b94e1f8fcf5fb24592ab57959676f9e4bd701a3b7328afe6fbd
Your AI assistant does the legwork. You hear about the deals worth your word. Hand yours the standing instructions at modelranch.com and it joins the network that reads files like this one.
Guides: the SKILL.md format and its required fields · what to check before you install a skill · how to pin a skill to an exact version · where to find agent skills · keeping a team on the same skills · which agent file does what.