null-deref SKILL.md skillA
null-deref from dannyan/secguard-clang is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.
mdr add dannyan/secguard-clang/null-deref@git:20261022.86d181cPins git:20261022.86d181c in mdr.lock. Pin the fingerprint instead.
- Audit grade
- A, 17 of 17 checks passed
- Kind
- SKILL.md skill
- Repository
- dannyan/secguard-clang
- Path
extension/shared/skills/null-deref/SKILL.md- Versions recorded
- 5
- Latest version
- git:20261022.86d181c, committed Oct 22, 2026
- First version recorded
- Oct 17, 2026
- Size
- 9,831 bytes
- Repository stars
- 25
- License
- Apache-2.0
Classify null dereference evidence — NULL_VALUE source, DEREFERENCE event, NULL_GUARD counter-evidence. Maps to CWE-476.
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
## Null Dereference Analysis (CWE-476) `contract_kind: implicit` — a parameter dereferenced without a dominating null check establishes an implicit non-null precondition (`ctx != NULL`). This skill judges NULL **reachability, not null-check presence**: a bare `T *p` parameter with no null check is **not** a finding by itself. A NULL source reaches a parameter dereference when either (intra-procedural) the function assigns NULL / a nullable allocator/return / an external call, or (inter-procedural, `origin: caller_null`) a caller passes a value it has not proven non-null for that parameter: - a caller passes literal `NULL` / `0` → the parameter is nullable on that path; - a caller passes an unguarded variable → NULL reachability is **unknown**; - a caller whose early-return check (`if (v == NULL) return;`) dominates the call proves non-null, so it is filtered and does **not** surface. The contract is **path-dependent**: a guarded caller does not rescue a function that another caller violates. These surface as `suspected`, never auto-confirmed. ### Evidence Pattern A null-deref candidate has: …
Read the whole file at its exact version.
How to install
mdr add dannyan/secguard-clang/null-deref@sha256:fa7f385ff62a36bfThe line at the top of this page pins the label git:20261022.86d181c, 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_m22kbgr7otrft2v5)
1 badge image fetches in 30 days. What the badge shows.
Versions
The registry has recorded 5 versions of this file, between Oct 17, 2026 and Oct 22, 2026, about one every day.
| version | committed | commit | size | audit | |
|---|---|---|---|---|---|
| git:20261022.86d181c latest | 2026-10-22 | 86d181c | 9,831 B | A | view · diff |
| git:20261021.da86460 | 2026-10-21 | da86460 | 9,110 B | A | view · diff |
| git:20261020.ebb27c1 | 2026-10-20 | ebb27c1 | 8,517 B | A | view · diff |
| git:20261020.8a6b43a | 2026-10-20 | 8a6b43a | 7,004 B | A | view · diff |
| git:20261017.d50924c | 2026-10-17 | d50924c | 6,582 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 (9831 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
dannyan/secguard-clang · 25 stars · license Apache-2.0 · pushed 2026-10-22 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_m22kbgr7otrft2v5 GET https://markdownregistry.com/api/v1/resolve?ref=dannyan/secguard-clang/null-deref GET https://markdownregistry.com/api/v1/blob/fa7f385ff62a36bf94857b95fbe05ed74c5aa1a2cb5a72e03f7681fb648ecd00
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.