Apache Tomcat up to 11.0.24/10.1.57/9.0.120/8.5.100 Rewrite Valve off-by-one

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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7.0$5k-$25k0.32+

Summaryinfo

A vulnerability marked as critical has been reported in Apache Tomcat up to 11.0.24/10.1.57/9.0.120/8.5.100. This impacts an unknown function of the component Rewrite Valve. This manipulation causes off-by-one. This vulnerability is handled as CVE-2026-65927. The attack can be initiated remotely. There is not any exploit available.

Detailsinfo

A vulnerability classified as critical was found in Apache Tomcat up to 11.0.24/10.1.57/9.0.120/8.5.100. Affected by this vulnerability is an unknown code of the component Rewrite Valve. The manipulation with an unknown input leads to a off-by-one vulnerability. The CWE definition for the vulnerability is CWE-193. A product calculates or uses an incorrect maximum or minimum value that is 1 more, or 1 less, than the correct value. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

Off-by-one Error vulnerability in Apache Tomcat impacting the [N] flag on the rewrite valves causes rewrite processing to restart at the second rule rather than the first rule. 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. 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 fix the issue.

It is possible to read the advisory at lists.apache.org. This vulnerability is known as CVE-2026-65927 since 07/23/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. The technical details are unknown and an exploit is not publicly available. The pricing for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 08/26/2026).

Upgrading to version 11.0.25, 10.1.58 or 9.0.121 eliminates this vulnerability.

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Type

Vendor

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.3
VulDB Meta Temp Score: 7.0

VulDB Base Score: 7.3
VulDB Temp Score: 7.0
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Off-by-one
CWE: CWE-193 / CWE-189
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Tomcat 11.0.25/10.1.58/9.0.121

Timelineinfo

07/23/2026 CVE reserved
08/25/2026 +33 days VulDB entry created
08/26/2026 +0 days Advisory disclosed
08/26/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: apache.org

Advisory: lists.apache.org
Status: Confirmed

CVE: CVE-2026-65927 (🔒)
GCVE (CVE): GCVE-0-2026-65927
GCVE (VulDB): GCVE-100-395371

Entryinfo

Created: 08/26/2026 00:20
Changes: 08/26/2026 00:20 (55)
Complete: 🔍
Cache ID: 216::103

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

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