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Vulnerability · Published Jan 22, 2026 · Assigned by GitHub_M

CVE-2025-64097NervesHub has Insufficient Token Entropy that Allows Authentication Bypass via Brute Force

Critical 9.5

In plain English

A critical-severity weak randomness in nerves_hub_web from nerves-hub. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 41% of all known vulnerabilities).

Severity (CVSS 4.0)9.5Critical
Exploit odds (30 days)0.5%top 59.3% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

NervesHub is a web service that allows users to manage over-the-air (OTA) firmware updates of devices in the field. A vulnerability present starting in version 1.0.0 and prior to version 2.3.0 allowed attackers to brute-force user API tokens due to the predictable format of previously issued tokens. Tokens included user-identifiable components and were not cryptographically secure, making them susceptible to guessing or enumeration. The vulnerability could have allowed unauthorized access to user accounts or API actions protected by these tokens. A fix is available in version 2.3.0 of NervesHub. This version introduces strong, cryptographically-random tokens using `:crypto.strong_rand_bytes/1`, hashing of tokens before database storage to prevent misuse even if the database is compromised, and context-aware token storage to distinguish between session and API tokens. There are no practical workarounds for this issue other than upgrading. In sensitive environments, as a temporary mitigation, firewalling access to the NervesHub server can help limit exposure until an upgrade is possible.

Affected products (as reported)

VendorProductVersions
nerves-hub nerves_hub_web >= 1.0.0, < 2.3.0

Weakness: CWE-330 · Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:H/SI:H/SA:H

References