Top 25 Race Condition Bug Bounty Reports

Cristian Cornea
4 min readMay 26, 2020
(Photo by Jonathan Chng on Unsplash)

In this article, we will discuss Race Condition vulnerability, how to find one, and present 25 disclosed reports based on this issue.

What is Race Condition?

According to OWASP:

“A race condition is a flaw that produces an unexpected result when the timing of actions impact other actions. An example may be seen on a multithreaded application where actions are being performed on the same data. Race conditions, by their very nature, are difficult to test for.”

In other words, race conditions are triggered when users unintentionally (impatient users) or intentionally (malicious actors) are tampering with application functionality timings, for example, sending a request at the same time by clicking very fast on a button.

Not only they are difficult to find in the wild, but also hard to detect.

How to test for Race Conditions

Usually, race conditions can affect applications that apply mathematical functions like add and subtract, for example money transfers, modifying a product price by applying a gift card or discount voucher, and so on.

User must tamper with the sequence of the events in order to find a race condition vulnerability, like applying the same discount code twice at the same moment, which will result in subtracting the same amount multiplied by two, but this depends very much on the back-end environment. It will occur mostly in multi-threaded applications. In our example, two threads would be trying to modify the shared piece of data (the product price) at the same time.

Top 25 Race Conditions Bug Bounty Reports

The reports were disclosed through the HackerOne platform and were selected according to their upvotes, bounty, severity level, complexity, and uniqueness.

#1

Title: Race condition in workers may cause an exploitable double free by abusing bytearray.compress()

Company: Flash (IBB)

Bounty: $10,000

Link: https://hackerone.com/reports/47227

#2

Title: Race condition in Flash workers may cause an exploitabl​e double free

Company: Flash (IBB)

Bounty: $10,000

Link: https://hackerone.com/reports/37240

#3

Title: Race Conditions in OAuth 2 API implementations

Company: The Internet

Bounty: $2,500

Link: https://hackerone.com/reports/55140

#4

Title: Race condition in performing retest allows duplicated payments

Company: HackerOne

Bounty: $2,100

Link: https://hackerone.com/reports/429026

#5

Title: Adobe Flash Player Race Condition Vulnerability

Company: Flash (IBB)

Bounty: $2,000

Link: https://hackerone.com/reports/119657

#6

Title: Race condition in activating email resulting in infinite amount of diamonds received

Company: InnoGames

Bounty: $2,000

Link: https://hackerone.com/reports/509629

#7

Title: Race Condition allows to redeem multiple times gift cards which leads to free “money”

Company: Reverb.com

Bounty: $1,500

Link: https://hackerone.com/reports/759247

#8

Title: Client-Side Race Condition using Marketo, allows sending user to data-protocol in Safari when form without onSuccess is submitted on www.hackerone.com

Company: HackerOne

Bounty: $1,250

Link: https://hackerone.com/reports/381356

#9

Title: Race condition на market.games.mail.ru

Company: Mail.ru

Bounty: $1,000

Link: https://hackerone.com/reports/317557

#10

Title: Race condition leads to duplicate payouts

Company: Hackerone

Bounty: $750

Link: https://hackerone.com/reports/220445

#11

Title: Race Condition Vulnerability On Pornhubpremium.com

Company: PornHub

Bounty: $520

Link: https://hackerone.com/reports/183624

#12

Title: Race Condition leads to undeletable group member

Company: HackerOne

Bounty: $500

Link: https://hackerone.com/reports/604534

#13

Title: Race Conditions in Popular reports feature.

Company: HackerOne

Bounty: $500

Link: https://hackerone.com/reports/146845

#14

Title: Race Condition in Flag Submission

Company: HackerOne

Bounty: $500

Link: https://hackerone.com/reports/454949

#15

Title: Race condition in claiming program credentials

Company: HackerOne

Bounty: $500

Link: https://hackerone.com/reports/488985

#16

Title: Race condition at create new Location

Company: Shopify

Bounty: $500

Link: Race condition at create new Location

#17

Title: race condition in adding team members

Company: Shopify

Bounty: $500

Link: https://hackerone.com/reports/176127

#18

Title: Race condition (TOCTOU) in NordVPN can result in local privilege escalation

Company: NordVPN

Bounty: $500

Link: https://hackerone.com/reports/768110

#19

Title: Register multiple users using one invitation (race condition)

Company: Keybase

Bounty: $350

Link: https://hackerone.com/reports/148609

#20

Title: Race conditions can be used to bypass invitation limit

Company: Keybase

Bounty: $350

Link: https://hackerone.com/reports/115007

#21

Title: Race condition when redeeming coupon codes

Company: Dropbox

Bounty: $216

Link: https://hackerone.com/reports/59179

#22

Title: Race Condition in Redeeming Coupons

Company: Instacart

Bounty: $200

Link: https://hackerone.com/reports/157996

#23

Title: Race Condition in account survey

Company: Slack

Bounty: $150

Link: https://hackerone.com/reports/395351

#24

Title: Bypass subdomain limits using race condition

Company: Charturbate

Bounty: $100

Link: https://hackerone.com/reports/395351

#25

Title: Race condition allowing user to review app multiple times

Company: Coinbase

Bounty: $100

Link: https://hackerone.com/reports/106360

Bonus: 5 Zero Dollars Race Conditions Reports

#1

Title: Race Condition : Exploiting the loyalty claim https://xxx.vendhq.com/loyalty/claim/email/xxxxx url and gain x amount of loyalty bonus/cash

Company: Vend VDP

Bounty: $0

Link: https://hackerone.com/reports/331940

#2

Title: JSBeautifier BApp: Race condition leads to memory disclosure

Company: PortSwigger Web Security

Bounty: $0

Link: https://hackerone.com/reports/187134

#3

Title: Race condition in GitLab import, giving access to other people their imports due to filename collision

Company: GitLab

Bounty: $0

Link: https://hackerone.com/reports/214028

#4

Title: Race Condition in Definition Votes

Company: Urban Dictionary

Bounty: $0

Link: https://hackerone.com/reports/152717

#5

Title: Race Conditions Exist When Accepting Invitations

Company: HackerOne

Bounty: $0

Link: https://hackerone.com/reports/119354

I would like to thank you for your time and please stay safe!

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Cristian Cornea

🇷🇴 Founder: Zerotak Security | Cyber Security Training Centre of Excellence (CSTCE) | SectionX.io | BSides Transylvania