CVE-2021-3047: PAN-OS: Weak Cryptography Used in Web Interface Authentication

Severity: low (CVSS 3.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2021-08-11 · updated 2026-06-17
Weakness: CWE-338

Description

A cryptographically weak pseudo-random number generator (PRNG) is used during authentication to the Palo Alto Networks PAN-OS web interface. This enables an authenticated attacker, with the capability to observe their own authentication secrets over a long duration on the PAN-OS appliance, to impersonate another authenticated web interface administrator's session. This issue impacts: PAN-OS 8.1 versions earlier than PAN-OS 8.1.19; PAN-OS 9.0 versions earlier than PAN-OS 9.0.14; PAN-OS 9.1 versions earlier than PAN-OS 9.1.10; PAN-OS 10.0 versions earlier than PAN-OS 10.0.4. PAN-OS 10.1 versions are not impacted.

Affected products

Palo Alto Networks PAN-OS: from 8.1.0 before 8.1.19; from 9.0.0 before 9.0.14; from 9.1.0 before 9.1.10; from 10.0.0 before 10.0.4 — fixed in 8.1.19, 9.0.14, 9.1.10, 10.0.4
Palo Alto Networks PAN-OS: from 8.1 before 8.1.19; from 9.0 before 9.0.14; from 10.0 before 10.0.4; from 9.1 before 9.1.10 — fixed in 8.1.19, 9.0.14, 10.0.4, 9.1.10

How to fix

Upgrade to a fixed version: Palo Alto Networks PAN-OS 8.1.19, 9.0.14, 9.1.10, 10.0.4; Palo Alto Networks PAN-OS 8.1.19, 9.0.14, 10.0.4, 9.1.10. Check the vendor advisory for mitigations.

References

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