github-starred/better-auth
2
0
Fork 0
mirror of https://github.com/better-auth/better-auth.git synced 2026-05-22 14:21:55 -05:00
Code Issues 2.5k Packages Projects Releases 112 Wiki Activity

[GH-ISSUE #8899] No maximum password length check before hashing (utils/password.ts) #11227

New Issue
Closed
opened 2026-04-13 07:34:20 -05:00 by GiteaMirror · 3 comments
GiteaMirror commented 2026-04-13 07:34:20 -05:00
Owner
Copy Link

Originally created by @alavesa on GitHub (Apr 1, 2026).
Original GitHub issue: https://github.com/better-auth/better-auth/issues/8899

Neither validatePassword nor checkPassword enforces a maximum length before passing the password to the hashing function. Bcrypt is intentionally slow — feeding it a multi-megabyte string can monopolize CPU.

Impact: DoS via extremely long password submissions.

Note: #779 discusses password complexity rules but not maximum length as a DoS vector.

Found by PatchPilots security audit.

Originally created by @alavesa on GitHub (Apr 1, 2026). Original GitHub issue: https://github.com/better-auth/better-auth/issues/8899 Neither `validatePassword` nor `checkPassword` enforces a maximum length before passing the password to the hashing function. Bcrypt is intentionally slow — feeding it a multi-megabyte string can monopolize CPU. **Impact:** DoS via extremely long password submissions. *Note: #779 discusses password complexity rules but not maximum length as a DoS vector.* Found by [PatchPilots](https://github.com/alavesa/patchpilots) security audit.
GiteaMirror added the securitybug labels 2026-04-13 07:34:20 -05:00
GiteaMirror commented 2026-04-13 07:34:22 -05:00
Author
Owner
Copy Link

@dosubot[bot] commented on GitHub (Apr 1, 2026):

Better-auth already enforces a maximum password length before hashing. The default limit is 128 characters, configured via the maxPasswordLength option [1]. Passwords exceeding this limit are rejected with a PASSWORD_TOO_LONG error at sign-up, password reset, and password change endpoints [2].

Also worth noting: better-auth uses scrypt (not bcrypt) for password hashing [3], so the bcrypt-specific framing in the issue doesn't quite apply here — but the 128-char cap addresses the general DoS concern regardless of algorithm.

Both minPasswordLength (default 8) and maxPasswordLength (default 128) are configurable through the emailAndPassword auth options [4] [1].

To reply, just mention @dosu.

How did I do? Good | Irrelevant | Incorrect | Verbose | Hallucination | Report 🐛 | Other
Chat with Dosu Open in Cursor Join Discord Share on X

<!-- gh-comment-id:4172728312 --> @dosubot[bot] commented on GitHub (Apr 1, 2026): <!-- Answer --> Better-auth already enforces a maximum password length **before** hashing. The default limit is **128 characters**, configured via the `maxPasswordLength` option [[1]](https://github.com/better-auth/better-auth/blob/8682b9d8d2e6216e23ca6d5768627f9d8aa94748/packages/better-auth/src/context/create-context.ts#L345). Passwords exceeding this limit are rejected with a `PASSWORD_TOO_LONG` error at sign-up, password reset, and password change endpoints [[2]](https://github.com/better-auth/better-auth/blob/8682b9d8d2e6216e23ca6d5768627f9d8aa94748/packages/better-auth/src/api/routes/password.ts#L282-L289). Also worth noting: better-auth uses **scrypt** (not bcrypt) for password hashing [[3]](https://github.com/better-auth/better-auth/blob/8682b9d8d2e6216e23ca6d5768627f9d8aa94748/packages/better-auth/src/crypto/password.ts#L4-L5), so the bcrypt-specific framing in the issue doesn't quite apply here — but the 128-char cap addresses the general DoS concern regardless of algorithm. Both `minPasswordLength` (default 8) and `maxPasswordLength` (default 128) are configurable through the `emailAndPassword` auth options [[4]](https://github.com/better-auth/better-auth/blob/8682b9d8d2e6216e23ca6d5768627f9d8aa94748/packages/better-auth/src/context/create-context.ts#L344) [[1]](https://github.com/better-auth/better-auth/blob/8682b9d8d2e6216e23ca6d5768627f9d8aa94748/packages/better-auth/src/context/create-context.ts#L345). <!-- Dosu Comment Footer --> *To reply, just mention [@dosu](https://go.dosu.dev/dosubot?utm_source=github&utm_medium=bot-comment&utm_campaign=github-assistant&utm_content=brand-link).* --- <sup>How did I do? [Good](https://app.dosu.dev/response-feedback?utm_source=github&utm_medium=bot-comment&utm_campaign=github-assistant&utm_content=feedback-great_response#message_id=adde034d-5b62-471c-a1a2-6a280aa80178&feedback_type=great_response) | [Irrelevant](https://app.dosu.dev/response-feedback?utm_source=github&utm_medium=bot-comment&utm_campaign=github-assistant&utm_content=feedback-irrelevant_answer#message_id=adde034d-5b62-471c-a1a2-6a280aa80178&feedback_type=irrelevant_answer) | [Incorrect](https://app.dosu.dev/response-feedback?utm_source=github&utm_medium=bot-comment&utm_campaign=github-assistant&utm_content=feedback-incorrect_sources#message_id=adde034d-5b62-471c-a1a2-6a280aa80178&feedback_type=incorrect_sources) | [Verbose](https://app.dosu.dev/response-feedback?utm_source=github&utm_medium=bot-comment&utm_campaign=github-assistant&utm_content=feedback-too_verbose#message_id=adde034d-5b62-471c-a1a2-6a280aa80178&feedback_type=too_verbose) | [Hallucination](https://app.dosu.dev/response-feedback?utm_source=github&utm_medium=bot-comment&utm_campaign=github-assistant&utm_content=feedback-hallucination#message_id=adde034d-5b62-471c-a1a2-6a280aa80178&feedback_type=hallucination) | [Report 🐛](https://app.dosu.dev/response-feedback?utm_source=github&utm_medium=bot-comment&utm_campaign=github-assistant&utm_content=feedback-bug_report#message_id=adde034d-5b62-471c-a1a2-6a280aa80178&feedback_type=bug_report) | [Other](https://app.dosu.dev/response-feedback?utm_source=github&utm_medium=bot-comment&utm_campaign=github-assistant&utm_content=feedback-other#message_id=adde034d-5b62-471c-a1a2-6a280aa80178&feedback_type=other)</sup> [![Chat with Dosu](https://dosu.dev/dosu-chat-badge.svg)](https://app.dosu.dev/cdda13d9-dd27-4d31-b09a-5d8bec92de21/ask?utm_source=github&utm_medium=bot-comment&utm_campaign=github-assistant&utm_content=chat-badge)&nbsp;[![Open in Cursor](https://dosu.dev/dosu-in-cursor.svg)](https://cursor.com/link/prompt?text=Better-auth%20already%20enforces%20a%20maximum%20password%20length%20%2A%2Abefore%2A%2A%20hashing.%20The%20default%20limit%20is%20%2A%2A128%20characters%2A%2A%2C%20configured%20via%20the%20%60maxPasswordLength%60%20option%20%5B%5B1%5D%5D%28https%3A//github.com/better-auth/better-auth/blob/8682b9d8d2e6216e23ca6d5768627f9d8aa94748/packages/better-auth/src/context/create-context.ts%23L345%29.%20Passwords%20exceeding%20this%20limit%20are%20rejected%20with%20a%20%60PASSWORD_TOO_LONG%60%20error%20at%20sign-up%2C%20password%20reset%2C%20and%20password%20change%20endpoints%20%5B%5B2%5D%5D%28https%3A//github.com/better-auth/better-auth/blob/8682b9d8d2e6216e23ca6d5768627f9d8aa94748/packages/better-auth/src/api/routes/password.ts%23L282-L289%29.%0A%0AAlso%20worth%20noting%3A%20better-auth%20uses%20%2A%2Ascrypt%2A%2A%20%28not%20bcrypt%29%20for%20password%20hashing%20%5B%5B3%5D%5D%28https%3A//github.com/better-auth/better-auth/blob/8682b9d8d2e6216e23ca6d5768627f9d8aa94748/packages/better-auth/src/crypto/password.ts%23L4-L5%29%2C%20so%20the%20bcrypt-specific%20framing%20in%20the%20issue%20doesn%27t%20quite%20apply%20here%20%E2%80%94%20but%20the%20128-char%20cap%20addresses%20the%20general%20DoS%20concern%20regardless%20of%20algorithm.%0A%0ABoth%20%60minPasswordLength%60%20%28default%208%29%20and%20%60maxPasswordLength%60%20%28default%20128%29%20are%20configurable%20through%20the%20%60emailAndPassword%60%20auth%20options%20%5B%5B4%5D%5D%28https%3A//github.com/better-auth/better-auth/blob/8682b9d8d2e6216e23ca6d5768627f9d8aa94748/packages/better-auth/src/context/create-context.ts%23L344%29%20%5B%5B1%5D%5D%28https%3A//github.com/better-auth/better-auth/blob/8682b9d8d2e6216e23ca6d5768627f9d8aa94748/packages/better-auth/src/context/create-context.ts%23L345%29.)&nbsp;[![Join Discord](https://img.shields.io/badge/join-5865F2?logo=discord&logoColor=white&label=)](https://go.dosu.dev/discord-bot?utm_source=github&utm_medium=bot-comment&utm_campaign=github-assistant&utm_content=join-discord)&nbsp;[![Share on X](https://img.shields.io/badge/X-share-black)](https://twitter.com/intent/tweet?text=%40dosu_ai%20helped%20me%20solve%20this%20issue!&url=https%3A//github.com/better-auth/better-auth/issues/8899)
GiteaMirror commented 2026-04-13 07:34:22 -05:00
Author
Owner
Copy Link

@alavesa commented on GitHub (Apr 1, 2026):

@dosu. The utility functions in password.ts don't enforce the limit themselves, but the upstream endpoint validation covers it. Closing this one.

<!-- gh-comment-id:4172742115 --> @alavesa commented on GitHub (Apr 1, 2026): @dosu. The utility functions in password.ts don't enforce the limit themselves, but the upstream endpoint validation covers it. Closing this one.
GiteaMirror commented 2026-04-13 07:34:23 -05:00
Author
Owner
Copy Link

@dosubot[bot] commented on GitHub (Apr 1, 2026):

That's exactly right — the maxPasswordLength validation happens at the endpoint level before the password ever reaches the hashing utilities, so the utility functions themselves don't need to duplicate that check. Thanks for confirming and closing this out!

To reply, just mention @dosu.

How did I do? Good | Irrelevant | Incorrect | Verbose | Hallucination | Report 🐛 | Other
Chat with Dosu Open in Cursor Join Discord Share on X

<!-- gh-comment-id:4172745517 --> @dosubot[bot] commented on GitHub (Apr 1, 2026): <!-- Answer --> That's exactly right — the `maxPasswordLength` validation happens at the endpoint level before the password ever reaches the hashing utilities, so the utility functions themselves don't need to duplicate that check. Thanks for confirming and closing this out! <!-- Dosu Comment Footer --> *To reply, just mention [@dosu](https://go.dosu.dev/dosubot?utm_source=github&utm_medium=bot-comment&utm_campaign=github-assistant&utm_content=brand-link).* --- <sup>How did I do? [Good](https://app.dosu.dev/response-feedback?utm_source=github&utm_medium=bot-comment&utm_campaign=github-assistant&utm_content=feedback-great_response#message_id=97523ec3-ac4c-493f-8101-3afb34428e54&feedback_type=great_response) | [Irrelevant](https://app.dosu.dev/response-feedback?utm_source=github&utm_medium=bot-comment&utm_campaign=github-assistant&utm_content=feedback-irrelevant_answer#message_id=97523ec3-ac4c-493f-8101-3afb34428e54&feedback_type=irrelevant_answer) | [Incorrect](https://app.dosu.dev/response-feedback?utm_source=github&utm_medium=bot-comment&utm_campaign=github-assistant&utm_content=feedback-incorrect_sources#message_id=97523ec3-ac4c-493f-8101-3afb34428e54&feedback_type=incorrect_sources) | [Verbose](https://app.dosu.dev/response-feedback?utm_source=github&utm_medium=bot-comment&utm_campaign=github-assistant&utm_content=feedback-too_verbose#message_id=97523ec3-ac4c-493f-8101-3afb34428e54&feedback_type=too_verbose) | [Hallucination](https://app.dosu.dev/response-feedback?utm_source=github&utm_medium=bot-comment&utm_campaign=github-assistant&utm_content=feedback-hallucination#message_id=97523ec3-ac4c-493f-8101-3afb34428e54&feedback_type=hallucination) | [Report 🐛](https://app.dosu.dev/response-feedback?utm_source=github&utm_medium=bot-comment&utm_campaign=github-assistant&utm_content=feedback-bug_report#message_id=97523ec3-ac4c-493f-8101-3afb34428e54&feedback_type=bug_report) | [Other](https://app.dosu.dev/response-feedback?utm_source=github&utm_medium=bot-comment&utm_campaign=github-assistant&utm_content=feedback-other#message_id=97523ec3-ac4c-493f-8101-3afb34428e54&feedback_type=other)</sup> [![Chat with Dosu](https://dosu.dev/dosu-chat-badge.svg)](https://app.dosu.dev/cdda13d9-dd27-4d31-b09a-5d8bec92de21/ask?utm_source=github&utm_medium=bot-comment&utm_campaign=github-assistant&utm_content=chat-badge)&nbsp;[![Open in Cursor](https://dosu.dev/dosu-in-cursor.svg)](https://cursor.com/link/prompt?text=That%27s%20exactly%20right%20%E2%80%94%20the%20%60maxPasswordLength%60%20validation%20happens%20at%20the%20endpoint%20level%20before%20the%20password%20ever%20reaches%20the%20hashing%20utilities%2C%20so%20the%20utility%20functions%20themselves%20don%27t%20need%20to%20duplicate%20that%20check.%20Thanks%20for%20confirming%20and%20closing%20this%20out%21)&nbsp;[![Join Discord](https://img.shields.io/badge/join-5865F2?logo=discord&logoColor=white&label=)](https://go.dosu.dev/discord-bot?utm_source=github&utm_medium=bot-comment&utm_campaign=github-assistant&utm_content=join-discord)&nbsp;[![Share on X](https://img.shields.io/badge/X-share-black)](https://twitter.com/intent/tweet?text=%40dosu_ai%20helped%20me%20solve%20this%20issue!&url=https%3A//github.com/better-auth/better-auth/issues/8899)
Sign in to join this conversation.
No Branch/Tag Specified
Branches Tags
Labels
Clear labels
adapter
astro
awaiting external contributor
blocked
breaking
breaking change
bug
c-devops
core
credentials
database
dependencies
devops
devtools
docs
documentation
duplicate
elysia
enhancement
enterprise
expo
express
fastify
good first issue
help wanted
hono
identity
infra
integration
invalid
javascript
locked
maintenance
need-more-information
needs: info
needs: repro
nextjs
nuxt
oauth
organization
P0
payments
perf
platform
plugin
pull-request
Mirrored from GitHub Pull Request
 question
ready
regression
remix
security
social-provider
solid
stale
svelte
tanstack-start
tracking
version-bump
vue
wontfix
No Label bug security
Milestone
No items
No Milestone
Projects
Clear projects
No project
Assignees
Clear assignees
GiteaMirror ninjasurge
No Assignees
1 Participants
Notifications
Due Date
No due date set.
Dependencies

No dependencies set.

Reference: github-starred/better-auth#11227
Delete Branch "%!s()"

Deleting a branch is permanent. Although the deleted branch may continue to exist for a short time before it actually gets removed, it CANNOT be undone in most cases. Continue?