NVD / CVE Program· CNA palo_alto

CVE-2021-3056: PAN-OS: Memory Corruption Vulnerability in GlobalProtect Clientless VPN During SAML Authentication

Noroxi assessment

Priority: Monitor (action score 35/100)

The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
Probability of exploitation in the next 30 days: 1.5% (FIRST EPSS); higher than 74.9% of all records.
Anyone who can reach it over the internet can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
Fixed version: Palo Alto Networks PAN-OS 10.0.1, 8.1.20, 9.0.14.

Low priority for now. Upgrade to Palo Alto Networks PAN-OS 10.0.1, 8.1.20, 9.0.14 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

A memory corruption vulnerability in Palo Alto Networks PAN-OS GlobalProtect Clientless VPN enables an authenticated attacker to execute arbitrary code with root user privileges during SAML authentication. This issue impacts: PAN-OS 8.1 versions earlier than PAN-OS 8.1.20; PAN-OS 9.0 versions earlier than PAN-OS 9.0.14; PAN-OS 9.1 versions earlier than PAN-OS 9.1.9; PAN-OS 10.0 versions earlier than PAN-OS 10.0.1. Prisma Access customers with Prisma Access 2.1 Preferred firewalls are impacted by this issue.

HighCVSS 8.8 · v3.1—No exploit Fix available

BDU:2021-05527

Published: Nov 10, 2021
Updated: Jun 17, 2026
EPSS: 1.5% · 74th percentile
CWE: CWE-120

Report tools

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Action score

Monitor

Low priority for now.

CVSS: 35 / 40 · 8.8 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 1.5%

CNA vs NVD score

NVD: 8.8
CNA · palo_alto: 8.8; agree

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

Not in KEV: no record of exploitation in the wild
No public exploit code on record
A fix has been released

If any of these changes, we'll tell you in the daily email digest.

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

Vendor	Product	CPE
paloaltonetworks	pan-os	cpe:2.3:o:paloaltonetworks:pan-os

Using pan-os? Add it to your stack and be the first to know about CVEs like this one. (Firewall)

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

paloaltonetworks pan-os8.1.0 and later · before 8.1.20
paloaltonetworks pan-os9.0.0 and later · before 9.0.14
paloaltonetworks pan-os9.1.0 and later · before 9.1.9
paloaltonetworks pan-os10.0.0

Versions reported by the vendor

Affected version ranges reported by the assigning authority (palo_alto). Independent of NVD's CPE analysis and usually ahead of it.

Palo Alto Networks PAN-OS
- 10.1.*not affected
- 9.0 and later · before 9.0.14affectedfixed in 9.0.14
- 8.1 and later · before 8.1.20affectedfixed in 8.1.20
- 9.1 and later · before 9.1.9affectedfixed in 9.1.9
- 10.0 and later · before 10.0.1affectedfixed in 10.0.1
Palo Alto Networks Prisma Access
- 2.1 Preferredaffected
- 2.2 all, 2.1 Innovationnot affected

Same product

paloaltonetworks: all records

Other highest-scoring records for the same primary product.

CVE-2024-3400PAN-OS: Arbitrary File Creation Leads to OS Command Injection Vulnerability in GlobalProtectKEV
100Now
CVE-2017-15944Palo Alto Networks PAN-OS before 6.1.19, 7.0.x before 7.0.19, 7.1.x before 7.1.14, and 8.0.x before 8.0.6 allows remote attackers to executeKEV
99Now
CVE-2024-0012PAN-OS: Authentication Bypass in the Management Web Interface (PAN-SA-2024-0015)KEV
97Now

Published before and after this one in the same product

← EarlierCVE-2021-3054Sep 8, 2021 · PAN-OS: Unsigned Code Execution During Plugin Installation Race Condition Vulnerability
26Monitor
← EarlierCVE-2021-3055Sep 8, 2021 · PAN-OS: XML External Entity (XXE) Reference Vulnerability in the PAN-OS Web Interface
26Monitor
Later →CVE-2021-3058Nov 10, 2021 · PAN-OS: OS Command Injection Vulnerability in Web Interface XML API
28Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / package	Fixed version	Source
Palo Alto Networks PAN-OS	10.0.1	Vendor (CNA)
Palo Alto Networks PAN-OS	8.1.20	Vendor (CNA)
Palo Alto Networks PAN-OS	9.0.14	Vendor (CNA)
Palo Alto Networks PAN-OS	9.1.9	Vendor (CNA)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

Nicholas NewsomPalo Alto Networks during an internal security review.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

—

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

CVE-2021-304691 days apartPAN-OS: Improper SAML Authentication Vulnerability in GlobalProtect Portal
26Monitor

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

Anyone who can reach it over the internet can trigger it.
A low-privileged account is enough.
No user action is required.
No special conditions are required; it is repeatable.

If successful

Confidentiality: high · data can be read
Integrity: high · data or configuration can be modified
Availability: high · the service can be disrupted

Attack vector: Network
Attack complexity: Low
Privileges required: Low
User interaction: None
Scope: Unchanged
Confidentiality impact: High
Integrity impact: High
Availability impact: High

Weakness class (CWE)

CWE-120 · Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')

CVSS vector

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

nvd-primary

Root cause

When data is copied, the source length is not compared with the size of the destination buffer. Excess data overwrites adjacent memory.

The bug in code

The whole CWE-120 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

1char buf[256];
2memcpy(buf, pkt->data, pkt->len);

Fixed

1char buf[256];
2if (pkt->len > sizeof(buf)) {
3  return -EINVAL;
4}
5memcpy(buf, pkt->data, pkt->len);

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Attack patterns (CAPEC)

ATT&CK techniques

—

Change log

Fix✗ → ✓Sep 28, 2026, 10:11 PM UTC

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References

security.paloaltonetworks.com/CVE-2021-3056

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records