Security readout for executives and security teams
Plain-English summary
This is a PAN-OS web interface flaw that lets a logged-in administrator read arbitrary firewall files and crash services. Repeated abuse can restart the device into maintenance mode, creating an outage risk. It is not listed as KEV, and the provided sources do not show active exploitation.
Executive priority
Treat this as a scheduled but firm firewall maintenance item. The flaw needs administrator access, but impact includes sensitive file exposure and potential firewall outage, so vulnerable appliances should be upgraded and management access reviewed.
Technical view
CVE-2021-3055 is an XXE issue in the PAN-OS web interface. Network access and high privileges are required. Successful abuse can expose local files and affect availability by crashing services; repeated requests can cause restart into maintenance mode. Prisma Access is stated as unaffected.
Likely exposure
Exposure is mainly Palo Alto Networks firewalls running vulnerable PAN-OS 8.1, 9.0, 9.1, or 10.0 builds with administrative web access available. The provided metadata also lists 10.1.*, but the description does not define a 10.1 fixed boundary.
Exploitation context
The source bundle does not cite public exploitation or KEV listing. Abuse requires authenticated administrator privileges, reducing opportunistic risk but raising concern for compromised admin accounts, malicious insiders, or overly broad administrative access.
Researcher notes
The key nuance is privilege level: PR:H limits broad exploitation, but confidentiality and availability impacts are high. Evidence is incomplete for 10.1 because the affected metadata lists it while the narrative fixed-version list does not.
Mitigation direction
- Upgrade PAN-OS 8.1 to 8.1.20 or later.
- Upgrade PAN-OS 9.0 to 9.0.14 or later.
- Upgrade PAN-OS 9.1 to 9.1.10 or later.
- Upgrade PAN-OS 10.0 to 10.0.6 or later.
- Check Palo Alto Networks guidance for any 10.1 applicability.
- Restrict PAN-OS web administration to trusted management networks.
Validation and detection
- Inventory PAN-OS versions across all managed firewalls.
- Confirm whether Prisma Access assets are excluded from this issue.
- Review administrative web interface exposure and access controls.
- Audit administrator accounts for unnecessary privileges or stale access.
- Check device logs for unexplained web interface crashes or maintenance-mode events.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
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CWE-611: Exact CWE lookup
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Open ATT&CK lookupFile access behavior lookup
The CVE wording references file access or upload behavior, so file telemetry and web shell review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2021-3055 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Medium
- CVSS
- 6.5 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:H1.25.2Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
6.5MediumVector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://security.paloaltonetworks.com/CVE-2021-3055CVE reference · x_refsource_MISC
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Improper Restriction of XML External Entity Reference
Improper Restriction of XML External Entity Reference represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.