Skip to content
Noroxi
NVD / CVE Program· CNA palo_alto

CVE-2020-1999: PAN-OS: Threat signatures are evaded by specifically crafted packets

Noroxi assessment

Priority: Monitor (action score 21/100)

  • 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: 1.3% (FIRST EPSS); higher than 71.1% of all records.
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Palo Alto Networks PAN-OS 8.1.17, 9.0.11, 9.1.5.

Low priority for now. Upgrade to Palo Alto Networks PAN-OS 8.1.17, 9.0.11, 9.1.5 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 vulnerability exists in the Palo Alto Network PAN-OS signature-based threat detection engine that allows an attacker to communicate with devices in the network in a way that is not analyzed for threats by sending data through specifically crafted TCP packets. This technique evades signature-based threat detection. This issue impacts: PAN-OS 8.1 versions earlier than 8.1.17; PAN-OS 9.0 versions earlier than 9.0.11; PAN-OS 9.1 versions earlier than 9.1.5; All versions of PAN-OS 7.1 and PAN-OS 8.0.

MediumCVSS 5.3 · v3.1—No exploit Fix available
Published
Nov 11, 2020
Updated
Jun 16, 2026
EPSS
1.3% · 71th percentile

Report tools

JSON

Action score

21

Monitor

Low priority for now.

CVSS
21 / 40 · 5.3 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 1.3%

CNA vs NVD score

NVD
5.3
CNA · palo_alto
5.3
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.

Follow CVE-2020-1999

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

One daily email digest (06:00 UTC); connect a webhook for KEV listings and weaponized exploits instantly.

Your free account also gets you

Running WordPress? Scan your site free with WP Lens

  • Stack alerts: add the products and versions you run, get the new CVEs that affect them
  • Uptime monitoring: 1 site, instant email when it goes down
  • Add your domain: subdomains and takeover risk scanned every week (1 domain)
  • 10 scans an hour on the security tools (3 a day without an account), an API key and MCP
  • All your scans in one panel: findings, what changed in the last scan, a report per domain or per client (PDF, share link)
All free tools

Sign up with email · Have an account? Sign in

Free account, no card. Unfollow any time.

Don't want an account? Get "Exploited this week" by email every MondayDon't want an account? RSS feed for paloaltonetworks records

Running WordPress? Scan your site free with WP Lens

Is your version affected? Check it

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.

We use this product, ask for help

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.

VendorProduct
paloaltonetworkspan-os

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

Watch new CVEs for pan-os

When you'll hear from us

  • when a new CVE affecting this product is published
  • when a record in your stack enters KEV or gets exploit code

One daily email digest (06:00 UTC); connect a webhook for KEV listings and weaponized exploits instantly.

Your free account also gets you

Running WordPress? Scan your site free with WP Lens

  • Stack alerts: add the products and versions you run, get the new CVEs that affect them
  • Uptime monitoring: 1 site, instant email when it goes down
  • Add your domain: subdomains and takeover risk scanned every week (1 domain)
  • 10 scans an hour on the security tools (3 a day without an account), an API key and MCP
  • All your scans in one panel: findings, what changed in the last scan, a report per domain or per client (PDF, share link)
All free tools

Sign up with email · Have an account? Sign in

Free account, no card. Unfollow any time.

Don't want an account? Get "Exploited this week" by email every Monday

Affected versions

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

  • paloaltonetworks pan-os7.1.0 and later · up to 7.1.26 inclusive
  • paloaltonetworks pan-os8.0.0 and later · up to 8.0.20 inclusive
  • paloaltonetworks pan-os8.1.0 and later · before 8.1.17
  • paloaltonetworks pan-os9.0.0 and later · before 9.0.11
  • paloaltonetworks pan-os9.1.0 and later · before 9.1.5

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

    • 10.0.*not affected
    • 7.1.*, 8.0.*affected
    • 8.1 and later · before 8.1.17affectedfixed in 8.1.17
    • 9.0 and later · before 9.0.11affectedfixed in 9.0.11
    • 9.1 and later · before 9.1.5affectedfixed in 9.1.5

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-2020-2043Sep 9, 2020 · PAN-OS: Passwords may be logged in clear text when using after-change-detail custom syslog field for config logs
    13Monitor
  • ← EarlierCVE-2020-2044Sep 9, 2020 · PAN-OS: Passwords may be logged in clear text while storing operational command (op command) history
    13Monitor
  • Later →CVE-2020-2000Nov 11, 2020 · PAN-OS: OS command injection and memory corruption vulnerability
    29Monitor

Remediation

Which version to upgrade to

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

Product / packageFixed versionSource
Palo Alto Networks PAN-OS8.1.17Vendor (CNA)
Palo Alto Networks PAN-OS9.0.11Vendor (CNA)
Palo Alto Networks PAN-OS9.1.5Vendor (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.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

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.

Variant candidates

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

No nightly-computed relations.

Chain candidates

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

—

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.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
low · data or configuration can be modified
Availability
none
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
Low
Availability impact
None

Weakness class (CWE)

CWE-754 · Improper Check for Unusual or Exceptional Conditions

CVSS vector

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

nvd-primary

Attack context

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

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

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

All records