CVE-2021-3057Public exploitNetwork attack vector

SYSTEM code execution via oversized portal configuration

Published Oct 13, 2021 · Updated Sep 17, 2024

Stack-based buffer overflow in Palo Alto Networks GlobalProtect App allows man-in-the-middle attackers to execute code with SYSTEM privileges. The privileged PanGPS service processes overlong strings from an encrypted portal configuration in a fixed-size stack buffer, overwriting the stack cookie and frame pointer. Exploitation requires control of the portal response through a man-in-the-middle position; successful attacks can crash PanGPS or run code as SYSTEM.

CVSS severity8.1
High
EPSS probability1.43%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stack-based buffer overflow in Palo Alto Networks GlobalProtect App allows man-in-the-middle attackers to execute code with SYSTEM privileges. The privileged PanGPS service processes overlong strings from an encrypted portal configuration in a fixed-size stack buffer, overwriting the stack cookie and frame pointer. Exploitation requires control of the portal response through a man-in-the-middle position; successful attacks can crash PanGPS or run code as SYSTEM.

The record

CVE
CVE-2021-3057
Published
Oct 13, 2021
Updated
Sep 17, 2024
Vendor
Palo Alto Networks
Product
GlobalProtect App
Classifications
CWE-121, T1557, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 13, 2021CVE publishedPublication date reported by the CVE source.
  2. Sep 17, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=5.1 <5.1.9 changes=[{"at":"5.1.9","status":"unaffected"}]
  2. Affected versionversion=5.2 <5.2.8 changes=[{"at":"5.2.8","status":"unaffected"}]
  3. Affected versionversion=5.3 <5.3.1 changes=[{"at":"5.3.1","status":"unaffected"}]

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Palo Alto Networks · GlobalProtect Appversion=5.1 <5.1.9 changes=[{"at":"5.1.9","status":"unaffected"}]; version=5.2 <5.2.8 changes=[{"at":"5.2.8","status":"unaffected"}]; version=5.3 <5.3.1 changes=[{"at":"5.3.1","status":"unaffected"}]

Published CVSS scores

8.1Palo Alto NetworksCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-121Stack-based Buffer Overflow
T1557Adversary-in-the-Middle
T1203Exploitation for Client Execution

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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