OCHK0

ERDENE-OCH BYAMBABAYAR · SECURITY RESEARCHER · ULAANBAATAR, MONGOLIA

OCHK0

SECURITY RESEARCH & FULL-STACK ENGINEERING

BUILDS SYSTEMS / BREAKS SYSTEMS / OPEN TO WORK*

*HIRING → CONTACT

0-DAY-001

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WRITEUPS

PUBLISHED VULNERABILITY RESEARCH · AND THE PRACTICE BEHIND IT

DISCLOSURESCVEs & COORDINATED BOUNTIES · PUBLICLY VERIFIABLE
001
CVE-2026-25896: One Dot That Unmasks Every XML Entity
CVE-2026-25896 · CRITICAL · CVSS 9.3 · 970 WORDS · 2026-02-20
002
CVE-2026-7997: Local Privilege Escalation in Chrome's macOS Updater
CVE-2026-7997 · HIGH · CVSS 7.8 · 762 WORDS · 2026-06-24
003
CVE-2026-39365: Walking Out of Vite's Dev Server Through a .map File
CVE-2026-39365 · MODERATE · CVSS 6.3 · 928 WORDS · 2026-04-07
004
The Patch That Wasn't: An RCE Bypass in an Intel Open-Source Project
BUG BOUNTY · 946 WORDS · 2026-03-11
LAB NOTESEXPLOITATION PRACTICE · pwn.college & CTF - NOT DISCLOSURES
005
Bypassing PIE: Leaking the Base and Landing the Shot
TECHNIQUE · 616 WORDS · 2025-05-01
006
Buffer Overflow: From Overwrite to Control Hijack
TECHNIQUE · 596 WORDS · 2025-04-30
007
x86-64 Shellcode Injection: Payloads That Actually Run
TECHNIQUE · 619 WORDS · 2025-05-03
→ FULL ARCHIVE/writeups

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DISCLOSURE LEDGER

EVERY BUG ON THE RECORD

NOIDVENDORCLASSCVSSSTATUSDAYS-TO-PATCH
001CVE-2026-25896fast-xml-parserCRITICAL[█████████▒] 9.3DISCLOSED12 DAYS
002CVE-2026-7997Google Chrome (macOS Updater)HIGH[████████▒▒] 7.8DISCLOSED-
003CVE-2026-39365ViteMODERATE[██████▒▒▒▒] 6.3DISCLOSED14 DAYS

RESPONSIBLE DISCLOSURE PRACTICED. EMBARGOES HONORED. RECEIPTS KEPT.

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ABOUT

WHO I AM WHEN THE TERMINAL IS OPEN

FIRST PERSON

I break software for a living and build it to relax. By day I lead engineering at Unread, shipping news platforms to production. By night I hunt bugs, play CTF on three continents, and write exploits until they land.

Everything I find gets reported, patched, and written up, in that order. Three CVEs and an Intel bounty are on this page with the receipts. No embargo theater. If it's here, it shipped and the vendor knows.

This site has no trackers, no analytics, and no framework it doesn't need. View source; that's what it's for.

THE SHORT VERSION

Ochko breaks software politely and documents it ruthlessly. Three published CVEs (one critical), an Intel patch-bypass bounty, and five international CTF finals; vendors patch faster when he's on the CC line.

FIG 03.1 · OCHK0 · LOCATION WITHHELD

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EXPERIENCE

MY CAREER AS A GIT LOG

LISTING 00 - git log --graph --all
*a3f9c21(org/unread)tech lead
Author: Erdene-Och Byambabayar <ochkofficial@gmail.com>
Date: 2023-08 → present
tech lead @ unread
+ shipped techworm.mn - a news platform for young readers - on Next.js + Tailwind
+ stood up Strapi CMS with custom APIs, cutting feature dev time ~50%
+ shipped 100.unread.today - the 'Unread 100: Changemakers' showcase
+ containerized a legacy CakePHP codebase and fixed critical bugs with no GitHub access
- a legacy CakePHP monolith
- deploys that needed a prayer
4 insertions(+), 2 deletions(-)
|
*8e2d4b0(org/pentra-cyber)cybersecurity engineer
Author: Erdene-Och Byambabayar <ochkofficial@gmail.com>
Date: 2023-04 → 2023-12
cybersecurity engineer @ pentra-cyber
+ built a large-scale scraping pipeline in Python + Selenium
+ deployed a serverless intelligence platform on Next.js + Firebase
+ wired scraped intel into the platform for analyst usability
- manual, one-off data collection
3 insertions(+), 1 deletion(-)
|
*5c1b7ef(org/teqstream)back-end engineer
Author: Erdene-Och Byambabayar <ochkofficial@gmail.com>
Date: 2022-08 → 2023-04
back-end engineer @ teqstream
+ cut a big-data job from 30 minutes to 5 (-83%)
+ migrated legacy MySQL procedures to Node.js (+70% readability)
+ built developer.timely.mn solo → +20% company revenue
+ found and fixed XSS + SQL injection in production
+ mentored interns and owned PR review
- 30-minute batch jobs
- unreviewed pull requests
5 insertions(+), 2 deletions(-)

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PROJECTS

THINGS BUILT FOR MONEY, PRACTICE, OR SPITE

PROJECT 001LIVE
BULLP

BULLP

A binary trading platform, rebuilt and optimized for real money.

[PHP][NODE][MYSQL]
MORE ▸

Rebuilt and optimized a binary options trading platform generating $500+ in daily revenue. PHP, Node.js and MySQL under the hood, tuned for throughput and reliability under live trading load.

PRICE: $500+/DAY

PROJECT 002LIVE
TIMELY DOCS

TIMELY DOCS

A developer documentation platform, built solo, that moved revenue.

[NODE][REACT][API]
MORE ▸

Independently designed and shipped developer.timely.mn - a documentation platform for TeqStream. Directly credited with a 20% increase in company revenue.

[ LIVE ↗ ]

PRICE: +20% REVENUE

PROJECT 003LIVE
TECHWORM

TECHWORM

A tech-news platform for young readers.

[NEXT][TAILWIND][STRAPI]
MORE ▸

A visually engaging tech-news platform built at Unread with Next.js, Tailwind CSS and a custom Strapi CMS. Fast, editorial, and built to scale.

[ LIVE ↗ ]

PRICE: 0x00 USD

PROJECT 004LIVE
UNREAD 100

UNREAD 100

A showcase of the changemakers shaping the decade.

[NEXT][FIREBASE]
MORE ▸

'Unread 100: Changemakers' - a platform spotlighting the new generation of politicians and changemakers. Built with Next.js and Firebase, animation-forward.

[ LIVE ↗ ]

PRICE: FREE AS IN SPEECH

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CTF RECORD

CAPTURE THE FLAG · INTERNATIONAL FINALS

DATEEVENTCATEGORYWHEREPLACE
2025HARUULZANGI 2025jeopardyMongolia2ND PLACENOTABLE
2025Hackday 2025jeopardyParis, FranceFINALIST
2024BlackHat MEA 2024jeopardyRiyadh, Saudi Arabia37 / 250NOTABLE
2024HackTheon Sejong 2024jeopardySejong, South KoreaFINALIST
2023VolgaCTF 2023attack-defenseSamara, RussiaFINALIST
2022HARUULZANGI 2022jeopardyMongolia2ND PLACENOTABLE

THIS PAGE IS ALSO A CTF. THREE PARTS: THE SOURCE, THE HEADERS, THE MISSING PAGE.

ASSEMBLE flag{...} AND SUBMIT IN THE SHELL - PRESS ~

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STACK

TOOLING, AND NO TRACKERS

# ochk0.stack - lockfileVersion 1

EXPLOITATION:

owasp-top-10

SHIPPING:

typescriptnext@15reacttailwindnodepythonphpflutterpostgresmysqlmongodbfirebase

INFRASTRUCTURE:

linuxdockerawsgcpredisgraphqlwebsocketsci/cdselenium

imposter_syndrome - DEPRECATED. DO NOT INSTALL.

BUILT WITH ANTON & IBM PLEX MONO. NO TRACKERS. NO ANALYTICS. VIEW SOURCE

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CONTACT

PLAINTEXT TIPS ACCEPTED. ENCRYPTED TIPS RESPECTED.

$ mail ochkofficial@gmail.com$ open Ochk0$ open intigriti/ochko$ curl -O resume.pdf

PGP

KEY FORTHCOMING - PLAINTEXT ACCEPTED.