How severe is CVE-2021-3053?

CVE-2021-3053 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2021-3053 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (59th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-3053?

CVE-2021-3053 affects Paloaltonetworks Pan-os. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-3053?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2021-3053 published?

CVE-2021-3053 was published on 2021-09-08 and last updated on 2026-06-17.

CVE-2021-3053

CVE-2021-3053 is a high-severity vulnerability in Paloaltonetworks Pan-os with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-755.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 7.1
EPSS exploit prediction: 1% (59th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-755
Affected product: Paloaltonetworks Pan-os
Published: 2021-09-08
Last modified: 2026-06-17

Description

An improper handling of exceptional conditions vulnerability exists in the Palo Alto Networks PAN-OS dataplane that enables an unauthenticated network-based attacker to send specifically crafted traffic through the firewall that causes the service to crash. Repeated attempts to send this request result in denial of service to all PAN-OS services by restarting the device and putting it into maintenance mode. 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 10.0.5. This issue does not affect Prisma Access.

Frequently asked questions

What is CVE-2021-3053?: An improper handling of exceptional conditions vulnerability exists in the Palo Alto Networks PAN-OS dataplane that enables an unauthenticated network-based attacker to send specifically crafted traffic through the firewall that causes the service to crash. Repeated attempts to send this request result in denial of service to all PAN-OS services by restarting the device and putting it into maintenance mode. 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 10.0.5. This issue does not affect Prisma Access.
How severe is CVE-2021-3053?: CVE-2021-3053 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2021-3053 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (59th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-3053?: CVE-2021-3053 affects Paloaltonetworks Pan-os. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-3053?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-3053 published?: CVE-2021-3053 was published on 2021-09-08 and last updated on 2026-06-17.

References

https://security.paloaltonetworks.com/CVE-2021-3053

Affected products (1)

cpe:2.3:o:paloaltonetworks:pan-os:*:*:*:*:*:*:*:*

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