CVE-2026-121802 @better-auth/expo before 1.7.16 allows certain account-takeover outcomes (e.g., unauthenticated changes of any account's email address), bec
Critical 9.1
Published
Updated
Check this codebase for CVE-2026-121802 and fix it if it is affected.
What it is: CVE-2026-121802 is a critical vulnerability in better-auth Better Auth, published on 4 Nov 2026.
Exploitation: There is no known exploitation of CVE-2026-121802 in the wild and no public exploit code.
Affected product: better-auth Better Auth. No package-level version data is available, so check the vendor advisory linked from the reference page.
Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.
Reference: https://insights.sbomify.com/CVE-2026-121802/ (Markdown: https://insights.sbomify.com/CVE-2026-121802/index.md)
- Exploited in the wild
- Not known
- Fix
- None listed
What is CVE-2026-121802?
CVE-2026-121802 is a critical vulnerability in better-auth Better Auth, published on 4 Nov 2026.
Official description
@better-auth/expo before 1.7.16 allows certain account-takeover outcomes (e.g., unauthenticated changes of any account's email address), because it signs a caller-supplied state value without checking whether that value had been issued by the server. NOTE: the application secret must be rotated after updating to a fixed version.
Weakness: CWE-346
Which versions are affected by CVE-2026-121802?
How do I fix CVE-2026-121802?
No fix has been published for CVE-2026-121802 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-121802 being exploited?
There is no known exploitation of CVE-2026-121802 in the wild and no public exploit code.
Sources
Also known as GHSA-4wq4-2ppv-q3hg, GHSA-hv45-wgqh-c9j5.