CVE-2026-0257
Paloaltonetworks Pan-Os ≤ 10.2.7
Raw vector
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:RedSummary
CVE-2026-0257 is a high-severity Reliance on Cookies without Validation and Integrity Checking (CWE-565) vulnerability in Paloaltonetworks Pan-Os. Its CVSS base score is 7.8 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Web Session Cookie (T1550.004); ranked in the top 0.2% of CVEs by exploit likelihood; CISA has added it to the Known Exploited Vulnerabilities catalog.
The strongest mitigations our analysis identified map to AC-3 (Access Enforcement) and SC-23 (Session Authenticity) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2026-0257 is an authentication bypass vulnerability affecting the GlobalProtect portal and gateway in Palo Alto Networks PAN-OS software. The flaw, tracked under CWE-565, permits an attacker to circumvent security controls and establish an unauthorized VPN connection. Panorama and Cloud NGFW deployments are explicitly not impacted.
An unauthenticated remote attacker can exploit the issue over the network without user interaction or credentials, achieving limited access that bypasses intended VPN authentication restrictions. The CVSS 4.0 score of 7.8 reflects high severity driven by network attack vector, low complexity, and subsequent impacts on confidentiality, integrity, and availability within the broader environment.
Vendor guidance is available in the Palo Alto Networks security advisory, while Siemens has published a related product certificate and CISA has added the CVE to its Known Exploited Vulnerabilities catalog. These sources collectively indicate that organizations should apply available patches or configuration mitigations without delay.
The current EPSS score of 0.5879, matching its recorded peak, combined with CISA KEV listing, signals active real-world exploitation interest following disclosure.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-30104
Vulnerability Data
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.
- CWE(s)
- KEV Date Added
- 29 May 2026
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Access Enforcement requires authorizations to be enforced by the system rather than by trusting client-supplied cookie values.
Session Authenticity directly requires protecting the integrity and authenticity of session tokens such as cookies, eliminating blind reliance on them.
Transmission Confidentiality and Integrity mandates cryptographic or equivalent protection for data in transit, which covers cookie values exchanged over HTTP.
Software, Firmware, and Information Integrity can detect unauthorized modification of cookie-based data after the fact via integrity verification.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Cookies commonly carry identity assertions; requiring their protection, conveyance, and verification directly eliminates the weakness.
Strong authentication mechanisms reduce reliance on unvalidated cookies for identity and access decisions.
Cryptographic integrity for data-in-transit directly mitigates tampering of cookies sent over the network.
Enforcing access policy and least privilege limits damage from cookie misuse but does not address cookie validation itself.
Integrity protections for data-at-rest can apply to cookie stores but do not cover validation during use.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Security testing can detect cookie-validation flaws but does not itself implement the required controls.
Application security requirements can mandate cookie validation, integrity protection, and server-side session handling.
Secure coding practices directly eliminate reliance on unvalidated cookies by requiring proper integrity checks and server-side verification.
Secure authentication mechanisms can enforce server-side validation and integrity checks that prevent reliance on untrusted cookies.