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CVE-2026-0257

Authentication bypass vulnerabilities in the GlobalProtect portal and gateway of Palo Alto Networks PAN-OS® software allows the attacker to bypass security…

High Known exploited
Severity
7.8 / 10
High · CVSS 4.0
Exploit chance (EPSS)
95.01%
Chance of exploitation in the next 30 days. Higher than 99.86% of scored vulnerabilities.
Known exploited
Yes
In CISA's catalog since May 29, 2026
Weakness
CWE-565 Reliance on Cookies without Validation and Integrity Checking
Fix
None yet
No fixed version published
Exploited in the wild. Palo Alto Networks PAN-OS Authentication Bypass Vulnerability (Palo Alto Networks PAN-OS). Required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable. Due for U.S. federal agencies by Jun 1, 2026. Known to be used in ransomware campaigns.

Description

Authentication bypass vulnerabilities in the GlobalProtect portal and gateway of Palo Alto Networks PAN-OS® software allows the attacker to bypass security restrictions and establish an unauthorized VPN connection.

Panorama and Cloud NGFW are not impacted by these issues.

How to fix

No fixed version has been published yet. Until one is, remove or replace the package, or turn off or isolate the affected feature. This page updates when a fix ships.

Severity breakdown

CVSS 4.0 7.8

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:H/SI:H/SA:N/E:A/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:N/R:A/V:D/RE:M/U:Red

Attack vector
Network
Attack complexity
Low
Attack requirements
None
Privileges required
None
User interaction
None
Confidentiality (vulnerable system)
Low
Integrity (vulnerable system)
None
Availability (vulnerable system)
None
Confidentiality (subsequent systems)
High
Integrity (subsequent systems)
High
Availability (subsequent systems)
None
Exploit maturity
Attacked
Scope
X

CVSS 3.1 9.1

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

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

Weakness

CWE-565: Reliance on Cookies without Validation and Integrity Checking

The product relies on the existence or values of cookies when performing security-critical operations, but it does not properly ensure that the setting is valid for the associated user.

How to prevent it
  • Architecture and Design: Avoid using cookie data for a security-related decision.
  • Implementation: Perform thorough input validation (i.e.: server side validation) on the cookie data if you're going to use it for a security related decision.
  • Architecture and Design: Add integrity checks to detect tampering.
  • Architecture and Design: Protect critical cookies from replay attacks, since cross-site scripting or other attacks may allow attackers to steal a strongly-encrypted cookie that also passes integrity checks. This mitigation applies to cookies that should only be valid during a single transaction or session. By enforcing timeouts, you may limit the scope of an attack. As part of your integrity check, use an unpredictable, server-side value that is not exposed to the client.

References

Advisories

Other links

Timeline

  1. Published
  2. Added to CISA's Known Exploited Vulnerabilities catalog
  3. Remediation due for U.S. federal agencies
  4. Last updated by the source
  5. Latest EPSS score
AdvisorySeverityWhy it's related
GHSA-gx76-c99x-2c96
AIOHTTP: Cookie from subdomain can remove Host-Only Scope from existing cookies
Low Same weakness, CWE-565
EEF-CVE-2026-75757
AshAdmin cookie reader matches names by substring, enabling actor/session shadowing from a sibling subdomain
Not rated yet Same weakness, CWE-565
GHSA-8c7c-h7px-267g
Concrete CMS is vulnerable to IDOR in surveys
Medium Same weakness, CWE-565
DRUPAL-CORE-2022-010
Cross-domain cookie leakage in Guzzle
High Same weakness, CWE-565
GHSA-j224-7qr4-8646
Centreon Does Not Set HTTPOnly Flag
High Same weakness, CWE-565
GHSA-4vf4-qmvg-mh7h
Cookie Prefix Spoofing in CGI::Cookie.parse
High Same weakness, CWE-565
GHSA-cg3q-59w7-rvc2
Reliance on Cookies without Validation and Integrity Checking in getgrav/grav
Medium Same weakness, CWE-565
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