CVE-2026-0257Known exploitationPublic exploitNetwork attack vector

Unauthorized VPN access via unsigned override cookies

Published May 13, 2026 · Updated May 13, 2026

Authentication bypass in GlobalProtect on affected PAN-OS and Prisma Access releases allows remote attackers to establish unauthorized VPN connections. The gpsvc main_DecryptAppAuthCookie path decrypts an authentication override cookie and trusts its contents without verifying a signature, allowing a reused certificate's public key to produce an accepted forged cookie. Exposure requires authentication override cookies and certificate reuse by another remotely visible feature; successful forgery grants VPN access.

CVSS severity9.1

Critical

EPSS probability95.16%

Next 30 days · Sep 16, 2026

Known exploitationReported

Based on sourced intelligence

Hinoki checkNot available

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Summary

What happened

The record

CVE: CVE-2026-0257
Published: May 13, 2026
Updated: May 13, 2026

Vendor: Palo Alto Networks
Product: PAN-OS
Classifications: CWE-565, CAPEC-114, T1133

Attack vector: network
Privileges: unauthenticated

Timeline

How it unfolded

May 13, 2026CVE publishedPublication date reported by the CVE source.
May 13, 2026Record updatedLatest update available in the CVE record.
May 17, 2026Exploitation reportedRapid7 MDR observed successful forged-cookie exploitation
May 29, 2026Exploitation reportedCISA Known Exploited Vulnerabilities Catalog entry

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

Affected versionversion=10.2.0 <10.2.18-h6, 10.2.16-h7, 10.2.13-h21, 10.2.10-h36, 10.2.7-h34 changes=[{"at":"10.2.18-h6","status":"unaffected"},{"at":"10.2.16-h7","status":"unaffected"},{"at":"10.2.13-h21","status":"unaffected"},{"at":"10.2.10-h36","status":"unaffected"},{"at":"10.2.7-h34","status":"unaffected"}]
Affected versionversion=11.1.0 <11.1.15, 11.1.13-h5, 11.1.10-h25, 11.1.7-h6, 11.1.6-h32, 11.1.4-h33 changes=[{"at":"11.1.15","status":"unaffected"},{"at":"11.1.13-h5","status":"unaffected"},{"at":"11.1.10-h25","status":"unaffected"},{"at":"11.1.7-h6","status":"unaffected"},{"at":"11.1.6-h32","status":"unaffected"},{"at":"11.1.4-h33","status":"unaffected"}]
Affected versionversion=11.2.0 <11.2.12, 11.2.10-h7, 11.2.7-h14, 11.2.4-h17 changes=[{"at":"11.2.12","status":"unaffected"},{"at":"11.2.10-h7","status":"unaffected"},{"at":"11.2.7-h14","status":"unaffected"},{"at":"11.2.4-h17","status":"unaffected"}]
Affected versionversion=12.1.0 <12.1.7, 12.1.4-h6 changes=[{"at":"12.1.7","status":"unaffected"},{"at":"12.1.4-h6","status":"unaffected"}]

What conditions does exploitation require?

Attack vectornetwork

Required privilegesunauthenticated

What is affected?

Palo Alto Networks · PAN-OSversion=10.2.0 <10.2.18-h6, 10.2.16-h7, 10.2.13-h21, 10.2.10-h36, 10.2.7-h34 changes=[{"at":"10.2.18-h6","status":"unaffected"},{"at":"10.2.16-h7","status":"unaffected"},{"at":"10.2.13-h21","status":"unaffected"},{"at":"10.2.10-h36","status":"unaffected"},{"at":"10.2.7-h34","status":"unaffected"}]; version=11.1.0 <11.1.15, 11.1.13-h5, 11.1.10-h25, 11.1.7-h6, 11.1.6-h32, 11.1.4-h33 changes=[{"at":"11.1.15","status":"unaffected"},{"at":"11.1.13-h5","status":"unaffected"},{"at":"11.1.10-h25","status":"unaffected"},{"at":"11.1.7-h6","status":"unaffected"},{"at":"11.1.6-h32","status":"unaffected"},{"at":"11.1.4-h33","status":"unaffected"}]; version=11.2.0 <11.2.12, 11.2.10-h7, 11.2.7-h14, 11.2.4-h17 changes=[{"at":"11.2.12","status":"unaffected"},{"at":"11.2.10-h7","status":"unaffected"},{"at":"11.2.7-h14","status":"unaffected"},{"at":"11.2.4-h17","status":"unaffected"}]; version=12.1.0 <12.1.7, 12.1.4-h6 changes=[{"at":"12.1.7","status":"unaffected"},{"at":"12.1.4-h6","status":"unaffected"}]

Palo Alto Networks · Prisma Accessversion=10.2.0 <10.2.10-h36 changes=[{"at":"10.2.10-h36","status":"unaffected"}]; version=11.2.0 <11.2.7-h13 changes=[{"at":"11.2.7-h13","status":"unaffected"}]

Published CVSS scores

7.8Palo Alto NetworksCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:H/SI:H/SA:N

9.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026

Latest reporting daySep 16, 2026

Latest daily unique IPsUnavailable

Prior 30-day averageUnavailable

SourceShadowserver honeypots (KEV)

Vectornetwork

Privilegesunauthenticated

Known exploitationReported

Public exploitPublished

Weakness, pattern, technique

CWE-565Reliance on Cookies without Validation and Integrity Checking

CAPEC-114Authentication Abuse

T1133External Remote Services

Public exploit references

Rapid7 GlobalProtect authentication-override cookie forgery proof of conceptfunctional · validated

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Reported exploitation

Rapid7 MDR observed successful forged-cookie exploitationreported exploitation
CISA Known Exploited Vulnerabilities Catalog entryknown exploited catalog

Technologies

Your stack

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Your stack

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