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CVE-2020-2040

PAN-OS: Buffer overflow when Captive Portal or Multi-Factor Authentication (MFA) is enabled

Critical9.8EPSS 3.9%
Published
Updated
Reserved
Assigned by
palo_alto

Description

A buffer overflow vulnerability in PAN-OS allows an unauthenticated attacker to disrupt system processes and potentially execute arbitrary code with root privileges by sending a malicious request to the Captive Portal or Multi-Factor Authentication interface. This issue impacts: All versions of PAN-OS 8.0; PAN-OS 8.1 versions earlier than PAN-OS 8.1.15; PAN-OS 9.0 versions earlier than PAN-OS 9.0.9; PAN-OS 9.1 versions earlier than PAN-OS 9.1.3.

Scores

CVSS scores of CVE-2020-2040, by who scored it
Scored byCVSSScoreVector
palo_altoCNA (assigner)3.1Critical9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVDNVD · Modified3.1Critical9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS (exploitation in 30 days)
3.9% · top 9.6% of all CVEs (6 Nov 2026)
Loading the EPSS history…

The list uses the assigner's score when there is one, then CISA's, then NVD's: Critical 9.8.

Weakness

Affected products

  • Palo Alto Networks · PAN-OS

    • affected 8.0.*
    • affected 9.0 – < 9.0.9
    • affected 9.1 – < 9.1.3
    • affected 8.1 – < 8.1.15
    • unaffected 10.0.0 – < 10.0*

What to do

Solution: This issue is fixed in PAN-OS 8.1.15, PAN-OS 9.0.9, PAN-OS 9.1.3, and all later PAN-OS versions. All Prisma Access services are now upgraded to resolve this issue and are no longer vulnerable. PAN-OS 7.1 and 8.0 are end-of-life and are no longer covered by our Product Security Assurance policies.

Workaround: Until PAN-OS software is upgraded to a fixed version, enabling signatures in content update version 8317 will block attacks against CVE-2020-2040.

Exploitation: Palo Alto Networks is not aware of any malicious attempts to exploit this vulnerability.

References (1)

Sources

The same CVE in the primary databases and aggregators, to check against.

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Record last updated .