Exploited Ransomware

CVE-2026-0257

Palo Alto Networks PAN-OS / GlobalProtect · Firewalls, VPNs and remote access

Palo Alto Networks PAN-OS Authentication Bypass Vulnerability

At a glance

Exploited. Added to CISA’s catalog of exploited vulnerabilities on May 29, 2026.

Used in ransomware attacks, according to CISA.

Affected product: Palo Alto Networks PAN-OS / GlobalProtect (category Firewalls, VPNs and remote access, indicative classification). Name in CISA’s catalog: Palo Alto Networks PAN-OS.

What should I do?

Apply the patches or mitigations from Palo Alto Networks; if none are available, stop using the product. For cloud services, follow the guidance from Palo Alto Networks.

Deadline set by CISA for US federal agencies: 3 days (due June 1, 2026). It only binds those agencies, but it is a useful measure of urgency.

Palo Alto Networks security advisories page (general page, not the advisory for this vulnerability)
The vendor’s specific advisory is listed in the NVD references: CVE-2026-0257 on the NVD website.

Original text of the required action (CISA)

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

Timeline

May 13, 2026 Vulnerability published Publication date (NVD)
May 29, 2026 Exploitation confirmed Added to CISA’s KEV catalog
June 1, 2026 CISA deadline Remediation deadline set for US federal agencies

The facts, with their sources

Exploitation confirmed: Yes, on May 29, 2026 Date added to the catalog of exploited vulnerabilities. Exploitation itself may have started earlier. Source: KEV catalog, collected September 29, 2026 at 14:57 UTC
Ransomware: Known use Source: KEV catalog, collected September 29, 2026 at 14:57 UTC
Hunt for compromise: Not requested by CISA Source: KEV catalog, collected September 29, 2026 at 14:57 UTC
CISA required action: Apply the patches or mitigations from Palo Alto Networks; if none are available, stop using the product. For cloud services, follow the guidance from Palo Alto Networks. Rewritten by this site from CISA’s original text. Source: KEV catalog, collected September 29, 2026 at 14:57 UTC
CISA deadline: June 1, 2026, 3 days Set for US federal agencies: a measure of urgency, not an obligation elsewhere. Source: KEV catalog, collected September 29, 2026 at 14:57 UTC
Vulnerability published: May 13, 2026 Source: National Vulnerability Database (NVD), collected September 29, 2026 at 15:00 UTC
Product according to CISA: Palo Alto Networks PAN-OS Filed by this site under “Firewalls, VPNs and remote access” (indicative classification). Source: KEV catalog, collected September 29, 2026 at 14:57 UTC
CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N Technical detail of the score: attack vector, complexity, impact. Source: National Vulnerability Database (NVD), collected September 29, 2026 at 15:00 UTC

Severity and activity

9.1 / 10 CVSS severity: critical

Score from the NVD. Collected Sep 29, 2026.

— Probability of exploitation in the next 30 days (EPSS)

FIRST’s EPSS model. Since exploitation is already confirmed, this figure is mostly useful to compare activity. Collected Sep 29, 2026.

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.

Palo Alto Networks PAN-OS contains an authentication bypass vulnerability that allows attackers to bypass security restrictions and establish an unauthorized VPN connection.

Summary from CISA (KEV catalog).

CERT-FR advisories

No advisory among the latest CERT-FR publications this site follows. That does not mean there are none.

Information reused under the Open Licence 2.0 (Etalab); the date of last update is shown for each advisory. This site is neither affiliated with nor endorsed by ANSSI.

Sources for this page

CISA KEV catalog: exploitation, date added, required action, deadline, ransomware.
NVD (NIST): CVSS severity, publication date, description, vendor references.
EPSS (FIRST): probability of exploitation.
CERT-FR: advisories and alerts (in French).
Brand and category: indicative classification by this site (method).