CVE-2026-0257
CVE-2026-0257 is a security flaw in Palo Alto Networks PAN-OS, the operating system on Palo Alto Networks’ firewalls. Attackers can get into Palo Alto Networks PAN-OS without a valid password. The US Cybersecurity and Infrastructure Security Agency (CISA) added it to its catalog of flaws known to be used in attacks on 29 May 2026, and says ransomware gangs have used it.[1]
Palo Alto Networks PAN-OS is business software or equipment. Most families won’t have it, but attackers break into it to get inside companies, and from there to what those companies hold about their customers, patients and staff. Fixed in version 12.1.7, 12.1.4-h6, 11.2.12, 11.2.10-h7, 11.2.7-h14, 11.2.4-h17, 11.1.15, 11.1.13-h5, 11.1.10-h25, 11.1.7-h6, 11.1.6-h32, 11.1.4-h33 and 10.2.18-h6, 10.2.16-h7, 10.2.13-h21, 10.2.10-h36, 10.2.7-h34 and others.
Description
CISA calls it an authentication bypass in Palo Alto Networks PAN-OS. In its words: “Palo Alto Networks PAN-OS contains an authentication bypass vulnerability that allows attackers to bypass security restrictions and establish an unauthorized VPN connection.”[1]
The CVE record adds: “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.”[2]
The underlying weakness is CWE-565, in MITRE’s list of common software weaknesses.
It scores 9.1 out of 10 on the Common Vulnerability Scoring System, which rates it critical, scored by NVD using CVSS 3.1.[2]
Affected versions
NVD’s record lists these fixed versions: in each line, everything before the version shown is affected.[2]
| Product | Fixed in |
|---|---|
| PAN-OS | 12.1.7, 12.1.4-h6 |
| PAN-OS | 11.2.12, 11.2.10-h7, 11.2.7-h14, 11.2.4-h17 |
| PAN-OS | 11.1.15, 11.1.13-h5, 11.1.10-h25, 11.1.7-h6, 11.1.6-h32, 11.1.4-h33 |
| PAN-OS | 10.2.18-h6, 10.2.16-h7, 10.2.13-h21, 10.2.10-h36, 10.2.7-h34 |
| Prisma Access | 10.2.10-h36 |
| Prisma Access | 11.2.7-h13 |
Most families won’t have Palo Alto Networks PAN-OS; it’s for whoever looks after IT at work.
Exploitation
CISA added it to its catalog of known exploited vulnerabilities on 29 May 2026, 16 days after it was made public. CISA lists a flaw only when it has reliable evidence of it being exploited, and gave US federal agencies until 1 Jun 2026 to fix it.[1] CISA says ransomware gangs have used it.
FIRST’s Exploit Prediction Scoring System, which estimates how likely a flaw is to be used in attacks in the next 30 days from what it sees across the internet, puts it at 95%. That’s in the top 1% of the flaws it scores.[4]
CISA assesses it as not automatable: each attack takes some work.
CISA doesn’t say who was attacked, or how.
Fix
Palo Alto Networks has published a fix or advice.[3] CISA’s 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.”[1]
- Check whether you use it.Palo Alto Networks PAN-OS is business software or equipment, so most families won’t have it. If you run a business, or work from home on company equipment, ask whoever looks after your IT.
- Send this page to your IT person.Ask them to confirm it’s fixed (fixed in version 12.1.7, 12.1.4-h6, 11.2.12, 11.2.10-h7, 11.2.7-h14, 11.2.4-h17, 11.1.15, 11.1.13-h5, 11.1.10-h25, 11.1.7-h6, 11.1.6-h32, 11.1.4-h33 and 10.2.18-h6, 10.2.16-h7, 10.2.13-h21, 10.2.10-h36, 10.2.7-h34 and others), or not in use. CISA gave US government agencies until 1 Jun 2026 to fix it.
- If it can’t be fixed, take it offline.CISA’s advice when there’s no fix is to stop using the product, or take it off the internet, until there is one.
You can’t fix someone else’s server, but you can watch for what follows a break-in like this: a breach notice, a password reset you didn’t ask for, or a scam message that knows things it shouldn’t. HARD watches for those for you and your family.
Timeline
| Date | Event |
|---|---|
| The flaw is made public in the National Vulnerability Database, with a severity score of 9.1.[2] | |
| CISA adds it to its catalog of flaws known to be used in attacks, noting that ransomware gangs have used it.[1] | |
| CISA’s deadline for US government agencies to fix it.[1] | |
| FIRST puts the odds of it being used in attacks in the next 30 days at 95%.[4] |
See also
Other Palo Alto Networks PAN-OS flaws
- CVE-2026-0322: code injection ·
- CVE-2026-0300: out-of-bounds write ·
- CVE-2025-0111: file read ·
- CVE-2025-0108: authentication bypass ·
- CVE-2024-3393: malicious DNS packet ·
- CVE-2024-9474: management interface OS command injection ·
Other Palo Alto Networks flaws
- CVE-2024-9465, Palo Alto Networks Expedition: SQL injection ·
- CVE-2024-9463, Palo Alto Networks Expedition: OS command injection ·
- CVE-2024-5910, Palo Alto Networks Expedition: missing authentication ·
Every Palo Alto Networks flaw on CISA’s list · Everything added in May 2026
References
- ^ Cybersecurity and Infrastructure Security Agency. “Palo Alto Networks PAN-OS Authentication Bypass Vulnerability”. Known Exploited Vulnerabilities Catalog, added 29 May 2026.
- ^ National Institute of Standards and Technology. “CVE-2026-0257 Detail”. National Vulnerability Database, published 13 May 2026.
- ^ Palo Alto Networks. Advisories and fixes: security.paloaltonetworks.com.
- ^ FIRST. “Exploit Prediction Scoring System”. EPSS 0.950, percentile 99.9, 31 Oct 2026.
- CVE Program. “CVE-2026-0257”. The official CVE record.
This article is built from CISA’s catalog (version 2026.10.30), NVD’s record and FIRST’s scores, kept in HARD’s database and checked every morning. The plain English is HARD’s.