CVE-2026-25854Network attack vector

Open redirect via uncollapsed leading slashes

Published Apr 9, 2026 · Updated Apr 9, 2026

Open redirect in Apache Tomcat's LoadBalancerDrainingValve allows remote attackers to send users to attacker-chosen URIs. The valve constructs a Location value from the request URI without collapsing multiple leading slashes, allowing a network-path reference to select another site. Exploitation requires the valve on a cluster node in the disabled draining state and user interaction with a crafted URL; the bounded consequence is navigation to an untrusted site.

CVSS severity6.9
Medium
EPSS probability0.53%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Open redirect in Apache Tomcat's LoadBalancerDrainingValve allows remote attackers to send users to attacker-chosen URIs. The valve constructs a Location value from the request URI without collapsing multiple leading slashes, allowing a network-path reference to select another site. Exploitation requires the valve on a cluster node in the disabled draining state and user interaction with a crafted URL; the bounded consequence is navigation to an untrusted site.

The record

CVE
CVE-2026-25854
Published
Apr 9, 2026
Updated
Apr 9, 2026
Vendor
The Apache Software Foundation
Product
Apache Tomcat
Classifications
CWE-601
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 9, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 9, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=10.1.0-M1 <=10.1.52
  2. Affected versionversion=11.0.0-M1 <=11.0.18
  3. Affected versionversion=8.5.30 <=8.5.100
  4. Affected versionversion=9.0.0.M23 <=9.0.115

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Apache Software Foundation · Apache Tomcatversion=10.1.0-M1 <=10.1.52; version=11.0.0-M1 <=11.0.18; version=8.5.30 <=8.5.100; version=9.0.0.M23 <=9.0.115

Published CVSS scores

6.9GitHubCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:N/SA:N
6.1CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-601URL Redirection to Untrusted Site ('Open Redirect')

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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