CVE-2026-68525: Apache Tomcat's FORM authentication process has an Incorrect Authorization vulnerability

Should you act?

Critical and remotely reachable

No known exploitation yet, but it is network-reachable without credentials. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

• No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
• EPSS 0.5%, percentile 40: FIRST’s model estimates a 0.5% chance of exploitation activity in the next 30 days, higher than 40% of all scored CVEs (low). EPSS is a probability, not a verdict.
• Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
• Only applies if your dependency tree includes org.apache.tomcat:tomcat (Maven) >= 11.0.0-M1, < 11.0.25, fixed in 11.0.25; org.apache.tomcat:tomcat (Maven) >= 10.1.0-M1, < 10.1.58, fixed in 10.1.58; org.apache.tomcat:tomcat (Maven) >= 9.0.0-M1, < 9.0.121, fixed in 9.0.121; org.apache.tomcat:tomcat (Maven) >= 8.5.0, <= 8.5.100, no fixed version listed. Check your lockfile, including transitive dependencies.
• Editorial verdict: Patch this week. Apache Tomcat August 2026: Security Constraint Bypasses — Upgrade Tomcat, including the copy embedded in Spring Boot apps, this week; the access-control bypasses matter wherever you rely on web.xml security constraints or container authentication, and none is known to be exploited.

What it is

Incorrect Authorization vulnerability in Apache Tomcat's FORM authentication process allows the bypassing of a security constraint that limits user has access to a resource POST but not GET. This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.24, from 10.1.0-M1 through 10.1.57, from 9.0.0.M1 through 9.0.120. The following versions were EOL at the time the CVE was created but are known to be affected: from 8.5.0 through 8.5.100, from 7.0.0 through 7.0.109. Other unsupported versions may also be affected. Users are recommended to upgrade to version 11.0.25, 10.1.58 or 9.0.121, which fixes the issue.

From the GitHub advisory

Incorrect Authorization vulnerability in Apache Tomcat's FORM authentication process allows the bypassing of a security constraint that limits user has access to a resource POST but not GET.

This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.24, from 10.1.0-M1 through 10.1.57, from 9.0.0.M1 through 9.0.120.

The following versions were EOL at the time the CVE was created but are known to be affected: from 8.5.0 through 8.5.100, from 7.0.0 through 7.0.109. Other unsupported versions may also be affected.

Users are recommended to upgrade to version 11.0.25, 10.1.58 or 9.0.121, which fixes the issue.

Weakness type: CWE-863.

Product: org.apache.tomcat:tomcat (Maven) · Assigned by: apache · Published: 2026-08-25

Affected and fixed versions

Severity scores

• Attack vector: network (remotely reachable)
• Attack complexity: low
• Privileges required: none (no login)
• User interaction: none
• Scope: unchanged

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

• CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
• CISA SSVC assessment: exploitation none, automatable yes, technical impact total.
• FIRST EPSS (model of 2026-10-21): 0.48% probability of exploitation activity in the next 30 days; percentile 40.

Timeline

• 2026-08-25 — CVE record published by apache
• 2026-08-25 — erroneo.us brief: Apache Tomcat August 2026: Security Constraint Bypasses
• 2026-08-26 — CVE record last updated
• 2026-08-26 — GitHub-reviewed advisory GHSA-h3x4-894j-xpx5 published (critical)

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.

Vendor and project advisories, patches

1. lists.apache.org lists.apache.org

Vulnerability records

1. GitHub Advisory GHSA-h3x4-894j-xpx5 github.com
2. CVE.org record CVE-2026-68525 cve.org
3. NVD entry CVE-2026-68525 nvd.nist.gov

Other references from the CVE record and advisory

1. openwall.com openwall.com
2. github.com github.com
3. github.com github.com
4. github.com github.com
5. tomcat.apache.org tomcat.apache.org
6. tomcat.apache.org tomcat.apache.org
7. tomcat.apache.org tomcat.apache.org

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