CVE-2026-94456: Weak RNG (CVSS 9.1)

Description

Postiz generates security-sensitive credentials using `Math.random()` instead of a cryptographically secure source. The same helper is used for OAuth access tokens, authorization codes, client secrets, organization API keys, and PKCE verifiers, meaning these credentials depend entirely on V8’s deterministic xorshift128+ PRNG state. An unauthenticated OAuth dynamic client registration endpoint exposes freshly generated client credentials, giving attackers enough consecutive PRNG output to reconstruct that internal state. Once recovered, they can deterministically derive past and future values produced by the same generator, potentially compromising credentials belonging to other users and organizations.

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CVSS v3.1 Score

9.1

CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

EPSS — Exploit Prediction

0.0052

Probability of exploitation

0.43%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-330 CWE-330

CWE-338 CWE-338

CWE-341 CWE-341

References

Other References

https://gadvisory.org/advisories/PSA-2026-TD98KY https://github.com/gitroomhq/postiz-app https://github.com/gitroomhq/postiz-app/commit/9259cf2429e8cc0c88414e88d5e6c783d7ffba63 https://github.com/gitroomhq/postiz-app/releases/tag/v2.24.0

Frequently Asked Questions

What is CVE-2026-94456? +

Postiz generates security-sensitive credentials using `Math.random()` instead of a cryptographically secure source. The same helper is used for OAuth access tokens, authorization codes, client secrets, organization API keys, and PKCE verifiers, meaning these credentials depend entirely on V8’s deterministic xorshift128+ PRNG state. An unauthenticated OAuth dynamic client registration endpoint exposes freshly generated client credentials, giving attackers enough consecutive PRNG output to reconstruct that internal state. Once recovered, they can deterministically derive past and future values produced by the same generator, potentially compromising credentials belonging to other users and organizations. It has a CVSS v3.1 base score of 9.1 (CRITICAL).

How severe is CVE-2026-94456? +

CVE-2026-94456 has a CVSS v3.1 score of 9.1 out of 10, rated CRITICAL. This is a critical vulnerability that should be patched immediately. The EPSS score is 0.0052, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-94456? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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