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🛡️ CVE-2026-43515 — tomcat

🔴 CVSS 9.5 — Critical ✅ No Known Exploit CWE-285 OSV
9.5
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

Apache Tomcat - Security constraints not correctly applied

Versions Affected:

Apache Tomcat 11.0.0-M1 to 11.0.21

Apache Tomcat 10.1.0-M1 to 10.1.54

Apache Tomcat 9.0.0.M1 to 9.0.117

Older, unsupported versions may also be affected

Description:

When multiple security constraints defined an HTTP method constraint for

the same extension pattern, only the first method constraint was applied.

Mitigation:

Users of the affected versions should apply one of the following

mitigations:

  • Upgrade to Apache Tomcat 11.0.22 or later
  • Upgrade to Apache Tomcat 10.1.55 or later
  • Upgrade to Apache Tomcat 9.0.118 or later

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality high, integrity high, availability none.

CVSS metrics in full

The score comes from this vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

  • Attack vector: Network — reachable from anywhere that can route to the service.
  • Attack complexity: Low — the attack works reliably, with no preparation.
  • Privileges required: None — an unauthenticated stranger can try it.
  • User interaction: None — nobody has to be tricked into anything.
  • Scope: Unchanged — the damage stays inside the vulnerable component.
  • Confidentiality impact: High — total loss, or loss the attacker controls.
  • Integrity impact: High — total loss, or loss the attacker controls.
  • Availability impact: None.

Weakness class

CVE-2026-43515 is classified as CWE-285: Improper Authorization. A request is carried out without confirming that the caller is permitted to perform it on that specific resource.

Affected software

CVE-2026-43515 is recorded against 4 packages.

  • org.apache.tomcat.embed:tomcat-embed-core (from 11.0.0-M1 up to 11.0.22)
  • org.apache.tomcat:tomcat (from 11.0.0-M1 up to 11.0.22)
  • org.apache.tomcat:tomcat-catalina (from 11.0.0-M1 up to 11.0.22)
  • tomcat

Timeline and source

Published on 12 May 2026 and last revised on 22 May 2026. No public exploit is currently recorded for this entry. Record sourced from OSV.

References

nvd.nist.gov (Advisory)
github.com (Web)
github.com (Web)
github.com (Web)
github.com (Package)
lists.apache.org (Web)
tomcat.apache.org (Web)
tomcat.apache.org (Web)
tomcat.apache.org (Web)
www.openwall.com (Web)

Other advisories for this package

org.apache.tomcat:tomcat has other advisories on record. If you are patching this one, these are worth checking on the same host:

Same weakness in other software

These advisories are the same class of weakness (CWE-285: Improper Authorization) in other software:

CVE-2026-43515 on other distributions

Each distribution ships its own build and its own fixed version. Pick the one you run:

Details

Severity CRITICAL
CVSS Score 9.5
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
CWE CWE-285
Public Exploit ✅ No
Source OSV
Published 2026-05-12
Updated 2026-08-20
Modified 2026-05-22
Fix URL N/A

Affected Packages

Software From version Fixed in
org.apache.tomcat:tomcat 11.0.0-M1 11.0.22
org.apache.tomcat:tomcat-catalina 11.0.0-M1 11.0.22
org.apache.tomcat.embed:tomcat-embed-core 11.0.0-M1 11.0.22
tomcat — —

Exploit Protection

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CVE-2026-43515 carries CVSS 9.5 Critical rating. BotEraser checks your installation against this and other known CVE records, and blocks IPs associated with exploit activity.

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ⓘ Data Notice: The information presented above has been compiled from publicly available internet sources. Boteraser aggregates this data solely for informational purposes and does not independently classify, evaluate, or endorse any findings about the vulnerabilities listed. The accuracy and completeness of this information is the sole responsibility of the original publishers. Boteraser and its operators accept no liability for any decisions made based on this data.

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