GHSA-mmpq-5hcv-hf2v BIT-parse-2026-39321 CVE-2026-39321
Parse Server has a login timing side-channel reveals user existence
- Severity
- 0.0 / 10
- Low · CVSS 4.0
- Exploit chance (EPSS)
- 0.23%
- Chance of exploitation in the next 30 days. Higher than 13.87% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-208 Observable Timing Discrepancy
- Fix
9.8.0-alpha.6- Upgrade parse-server to this version or later
Description
Impact
The login endpoint response time differs measurably depending on whether the submitted username or email exists in the database. When a user is not found, the server responds immediately. When a user exists but the password is wrong, a bcrypt comparison runs first, adding significant latency. This timing difference allows an unauthenticated attacker to enumerate valid usernames.
Patches
A dummy bcrypt comparison is now performed when no user is found, normalizing response timing regardless of user existence. Additionally, accounts without a stored password (e.g. OAuth-only) now also run a dummy comparison to prevent the same timing oracle.
Workarounds
Configure rate limiting on the login endpoint to slow automated enumeration. This reduces throughput but does not eliminate the timing signal for individual requests.
Affected versions
npm
| Package | Vulnerable | Fixed in |
|---|---|---|
| parse-server | >= 9.0.0, < 9.8.0-alpha.6 |
9.8.0-alpha.6 |
| parse-server | < 8.6.74 |
8.6.74 |
How to fix
Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.
parse-server npm → 9.8.0-alpha.6
- npm
npm install parse-server@9.8.0-alpha.6- yarn
yarn add parse-server@9.8.0-alpha.6- pnpm
pnpm add parse-server@9.8.0-alpha.6
Severity breakdown
CVSS 4.0 0.0
CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
- Attack vector
- Network
- Attack complexity
- High
- Attack requirements
- Present
- Privileges required
- None
- User interaction
- None
- Confidentiality (vulnerable system)
- Low
- Integrity (vulnerable system)
- None
- Availability (vulnerable system)
- None
- Confidentiality (subsequent systems)
- None
- Integrity (subsequent systems)
- None
- Availability (subsequent systems)
- None
CVSS 3.1 3.7
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
- Attack vector
- Network
- Attack complexity
- High
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- Low
- Integrity
- None
- Availability
- None
Weakness
CWE-208: Observable Timing Discrepancy
Two separate operations in a product require different amounts of time to complete, in a way that is observable to an actor and reveals security-relevant information about the state of the product, such as whether a particular operation was successful or not.
References
Advisories
Packages
Other links
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GHSA-r899-h629-j84r Parse Server vulnerable to stored XSS via malformed Content-Type bypassing file upload extension blocklist | Low | Also affects parse-server |
| GHSA-97pr-9hgg-3p8r parse-server: LiveQuery discloses object data to a subscriber across an ACL read-access change | Low | Also affects parse-server |
| GHSA-v8x7-r927-cc93 parse-server: Stored XSS via non-standard file extension bypassing file upload extension blocklist | Low | Also affects parse-server |
| GHSA-cgxm-vr2f-6fj8 parse-server: Denial of service via exponential-time processing of deeply nested query operators | High | Also affects parse-server |
| GHSA-wmwx-jr2p-4j4r parse-server: Relation `$relatedTo` query bypasses `protectedFields` and owning-object ACL | Medium | Also affects parse-server |
| GHSA-75v4-m273-5j49 parse-server: Endpoints `/login` and `/verifyPassword` disclose MFA secrets and protected fields when `_User` get is denied | Medium | Also affects parse-server |
| GHSA-7wqv-xjf3-x35v parse-server: Stored XSS via trailing-dot filename bypassing file upload extension blocklist | Low | Also affects parse-server |
| GHSA-p84r-h6rx-f2xr parse-server: Server option routeAllowList is bypassable through batch sub-requests | Medium | Also affects parse-server |
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