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CVE-2026-43930 — parse-server

Fix: parse-community/parse-server#10448

CVE-2026-43930 is a CWE-362 vulnerability in parse-server. A fix is available for parse-server — see the affected versions and patch details below.

Parse Server: MFA SMS one-time password accepted twice under concurrent login

Also known asBIT-parse-2026-43930GHSA-jpq4-7fmq-q5fj
Published
May 12, 2026
Updated
Aug 12, 2026
Affected
2 pkgs
Patched
2 / 2
Exploits
None indexed
Exploitation data as of Sep 21, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

  • CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-43930.

EPSS Exploitation Probability

via FIRST.org ↗
0.2%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs15th percentile — riskier than 15% of all scored CVEsHighest risk

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Real-World Exposure

2 pkgs affected

How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.

62other npm packages depend on this — each one inherits the vulnerability until it's patched upstream
parse-servernpm
29Kdownloads / week

Description

Impact

A race condition in the MFA SMS one-time password (OTP) login path allows two concurrent /login requests carrying the same OTP to both succeed and both receive valid session tokens, breaking the single-use property of the OTP. The vulnerability requires the attacker to already possess the victim's password and intercept the active SMS OTP (e.g. via SIM swap, network mirror, or phishing relay) and to race the legitimate login request, so the practical attack surface is narrow.

This advisory is the same class of incomplete fix as GHSA-2299-ghjr-6vjp (TOTP recovery codes) and GHSA-w73w-g5xw-rwhf (MFA recovery in authData-only login). Those previous fixes added optimistic locking only for array-typed authData fields; SMS MFA stores the OTP as a string, so the guard skipped it.

Patches

The optimistic lock has been generalized to cover primitive (string, number, boolean) and array authData fields. The lock is implemented as a shared helper applyAuthDataOptimisticLock that adds equality predicates on the original values of changed fields to the update WHERE clause. Concurrent writers racing the same single-use token now miss the WHERE condition and surface as Invalid auth data.

Workarounds

  • Disable SMS MFA and use TOTP instead (TOTP tokens are time-window validated, not stored single-use).
  • Place a rate limiter on the /login endpoint to reduce concurrent-request burst capacity.

Resources

Affected Packages

2 total 2 fixed
EcosystemPackageVulnerable rangeFix
📦npmparse-server≥ 9.0.0&&< 9.9.0-alpha.29.9.0-alpha.2npm install parse-server@9.9.0-alpha.2
📦npmparse-serverall versions8.6.76npm install parse-server@8.6.76

Detection & mitigation playbook

Open-source dependency

  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for parse-server, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update parse-server to 9.9.0-alpha.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-43930 is resolved across your whole dependency graph.

  3. Workarounds

    If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

  4. How O3 protects you

    O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-43930 can be triaged on real exposure rather than presence alone.

Tailored to CVE-2026-43930. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

### Impact A race condition in the MFA SMS one-time password (OTP) login path allows two concurrent `/login` requests carrying the same OTP to both succeed and both receive valid session tokens, breaking the single-use property of the OTP. The vulnerability requires the attacker to already possess the victim's password and intercept the active SMS OTP (e.g. via SIM swap, network mirror, or phishing relay) and to race the legitimate login request, so the practical attack surface is narrow. This advisory is the same class of incomplete fix as [GHSA-2299-ghjr-6vjp](https://github.com/parse-comm
O3 Security · Impact-Aware SCA

Is CVE-2026-43930 in your dependencies?

O3 Security finds CVE-2026-43930 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.

Scan my dependencies How O3 SCA works
CVE-2026-43930: parse-server | O3 Security