CVE-2026-121802
Better-Auth Expo Improper Authentication Verification Vulnerability
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.
INFO
Published Date :
Nov. 4, 2026, 3:17 a.m.
Last Modified :
Nov. 4, 2026, 3:17 a.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | CRITICAL | 8254265b-2729-46b6-b9e3-3dfca2d5bfca | ||||
| CVSS 3.1 | CRITICAL | [email protected] |
Solution
- Update @better-auth/expo to version 1.7.16 or later.
- Rotate the application secret after updating.
- Ensure caller-supplied state is server-issued.
- Validate signed state before use.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-121802.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-121802 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-121802
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-121802 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-121802 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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New CVE Received by [email protected]
Nov. 04, 2026
Action Type Old Value New Value Added 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. Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N Added CWE CWE-346 Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/121xxx/CVE-2026-121802.json">CVE-2026-121802</a> Added Reference https://github.com/better-auth/better-auth/blob/main/packages/expo/CHANGELOG.md Added Reference https://github.com/better-auth/better-auth/releases/tag/v1.7.16 Added Reference https://github.com/better-auth/better-auth/security/advisories/GHSA-4wq4-2ppv-q3hg