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Critical

Improper Authorization in Apache Tomcat security constraints

IdentifiersCVE-2026-43515CWE-863

CVE-2026-43515 is an improper authorization flaw in Apache Tomcat’s handling of security constraints. When multiple security constraints define an HTTP method constraint for the same extension pattern, Tomcat applies only the first method constraint instead of correctly enforcing all applicable constraints. As a result, security constraints for requests matching the same extension may be evaluated incorrectly, leading to incomplete enforcement of intended HTTP method restrictions. Reported affected versions are Tomcat 11.0.0-M1 through 11.0.21, 10.1.0-M1 through 10.1.54, 9.0.0.M1 through 9.0.117, 8.5.0 through 8.5.100, and 7.0.0 through 7.0.109.

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Incorrect enforcement of configured security constraints can allow authorization policy bypass for affected resources. In deployments that rely on multiple method-specific constraints for the same extension pattern, requests using HTTP methods that should have been restricted may be processed under an incomplete rule set. Depending on application configuration, this can result in unauthorized access to protected functionality, bypass of expected method restrictions, and potentially exposure of sensitive information or authentication/authorization controls.

Mitigation

If you can’t patch tonight, do this now.

If immediate upgrade is not possible, review and simplify security-constraint definitions so that the same extension pattern does not depend on multiple overlapping HTTP method constraints. Validate effective authorization behavior for all HTTP methods on protected extension mappings, and restrict external access to affected applications until patched. However, the primary vendor-recommended mitigation is to upgrade.

Remediation

Patch, then assume compromise.

Upgrade Apache Tomcat to a fixed release. Apache recommends upgrading to 11.0.22, 10.1.55, or 9.0.118 or later, depending on the deployed branch. For older affected branches such as 8.5.x and 7.0.x, migrate to a supported fixed branch because no fixed versions for those unsupported lines are provided in the supplied content.
PUBLIC EXPLOITS

Exploits

No public exploits tracked yet. Mallory keeps watching.

VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType
Apache Software FoundationTomcatapplication

Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.

ACTIVITY FEED

Recent activity

7 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.

7 SOURCESView more in app
What this page doesn’t show

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Exposure mapping

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Threat actor evidence

Every observed campaign linking this CVE to a named adversary.

Associated malware

Malware families riding this exploit, with evidence and IOCs.

Detection signatures

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity3

Community discussion across Reddit, Mastodon, and other social sources.

EXTERNAL REFERENCES
MITRE CVE
cve.org · CVE-2026-43515
NVD
nvd.nist.gov/vuln/detail/CVE-2026-43515
MITRE CWE · CWE-863
cwe.mitre.org
Vendor Advisory
lists.apache.org/thread/746nxfxod0wsocxtmv8pb8nkgmwpc6bb
Third Party Advisory
openwall.com/lists/oss-security/2026/05/12/11