xalgorix/xalgorix is a self-hosted AI penetration-testing tool in which an LLM agent performs reconnaissance, looks for vulnerabilities, and coordinates exploitation, while a separate verifier re-tests findings before reporting them. It is for security teams, ethical hackers, and bug bounty work using a private, bring-your-own-LLM setup. The catalogue skills extend the agent's pentesting workflow.
Getting it into your agent
It runs from inside its repository, so the clone comes first — what it calls does not travel with the file alone.
git clone --depth 1 https://github.com/xalgorix/xalgorixnpx agentmods add skills/xalgorix/xalgorix/exploiting-integer-overflow-vulnerabilitiesWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/xalgorix/xalgorix/exploiting-integer-overflow-vulnerabilities)<a href="https://agentmods.dev/skills/xalgorix/xalgorix/exploiting-integer-overflow-vulnerabilities"><img src="https://agentmods.dev/badge/skills/xalgorix/xalgorix/exploiting-integer-overflow-vulnerabilities/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/xalgorix/xalgorix/exploiting-integer-overflow-vulnerabilities"><img src="https://agentmods.dev/badge/skills/xalgorix/xalgorix/exploiting-integer-overflow-vulnerabilities.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector warn
SkillSpector: 1 finding, up to high
These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →
- high YARA Match · line 84 YARA rule matched a hack tool or exploit indicator (offensive tools, reconnaissance, privilege escalation, or exploit frameworks).Fix: Remove offensive tool references and exploit code. Legitimate agent skills should not contain penetration testing tools, exploit frameworks, or reconnaissance utilities.
What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00069 | $0.02441 |
| Opus 5.5 | $0.00028 | $0.00976 |
| Sonnet 5.5 | $0.00014 | $0.00488 |
| Haiku 4.5 | $0.00007 | $0.00244 |
Grade A, and why
exploiting-integer-overflow-vulnerabilities scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 1mo ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 180 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Exploiting Integer Overflow Vulnerabilities
When to Use
- During authorized assessments of native code (C/C++/Rust/Go) where attacker-controlled integers feed size, length, count, index, or offset calculations.
- When an allocation size is computed from arithmetic (
count * elem_size,len - header,size + padding) that can wrap, producing an undersized buffer later written with the logical (un-wrapped) size — a classic integer-overflow-to-heap-overflow chain. - When a length/bounds check uses a narrow type (e.g. 1-byte size field) that can be overflowed to bypass validation while the real copy uses a larger value.
- When signed/unsigned confusion causes a negative input to be treated as a huge positive size.
Critical: Concepts/Steps Most Often Missed
- The overflow itself is rarely the impact — find the dangerous downstream use. An int wrap is only exploitable when
the wrapped value sizes an allocation/copy/index. Always trace the tainted integer to a
malloc,memcpy,read, loop bound, or array index. - Truncation across type widths.
uint32_t product = (uint32_t)(count * elem_size)can wrap to a tiny value while a separatesize_t to_copy = count * elem_sizekeeps the full value — allocation is small, copy is huge. Watch every cast to a narrower type. - Underflow on subtraction is just as dangerous.
size_t payload = total_len - HEADERwithtotal_len < HEADERunderflows to a near-SIZE_MAXvalue, turning a "shrink" into an unbounded copy. - Signedness. A signed
intread withscanf("%d")then cast tounsignedmakes negatives become large positives, defeatingif (x > LIMIT)checks. - Alignment/rounding re-introduces overflow after an initial guard. Custom allocators that pass an initial wrap
check then do
total += (8 - total) % totalcan wrap again for values nearSIZE_MAX, yielding a tiny chunk (e.g. CVE-2025-54957). - Go/Rust wrap silently in release/normal builds. Go has no overflow panic by default; instrument with go-panikint;
Rust wraps in release unless
overflowing_*/checked arithmetic is used.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 1mo ago First seen · 180 lines · 69 tokens per session scan A 6daed78a792a
exploiting-integer-overflow-vulnerabilities is a skill published in the GitHub repository xalgorix/xalgorix (1,234 stars, last pushed today), licensed Apache-2.0. It adds 69 tokens to every session and 2,441 once invoked, about $0.0003 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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