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🛡️ CVE-2026-59083 — tomcat

🔴 CVSS 9.5 — Critical ✅ No Known Exploit CWE-177 OSV
9.5
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

Apache Tomcat: Incorrect URL decoding in RewriteValve may allow security control bypass

Improper Handling of URL Encoding (Hex Encoding) vulnerability in Apache Tomcat's rewrite valve allowed security constraint bypass for some configurations.

This issue affects Apache Tomcat: from 11.0.0 through 11.0.23, from 10.1.0 through 10.1.56, from 9.0.0 through 9.0.119, from 8.5.0 through 8.5.100. Other versions that have reached end of support may also be affected.

Users are recommended to upgrade to version 11.0.24, 10.1.57 or 9.0.120, which fix the issue.

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-2026-59083 is classified as CWE-177: Improper Handling of URL Encoding (Hex Encoding). The product does not properly handle when all or part of an input has been URL encoded.

Affected software

CVE-2026-59083 is recorded against 1 package.

  • tomcat

Timeline and source

Published on 15 July 2026. No public exploit is currently recorded for this entry. Record sourced from OSV.

References

www.openwall.com (Web)
lists.apache.org (Web)
nvd.nist.gov (Web)

Other advisories for this package

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-177: Improper Handling of URL Encoding (Hex Encoding)) in other software:

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-177
Public Exploit ✅ No
Source OSV
Published 2026-07-15
Updated 2026-08-20
Modified 2026-07-15
Fix URL N/A

Affected Packages

Software From version Fixed in
tomcat — —

Similar Threats

Exploit Protection

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CVE-2026-59083 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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