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No exploitation reportedFix available

CVE-2026-42498

No exploitation reported by the sources we read.

  • Published2026-05-12
  • Fixed in11.0.22 · 10.1.55 · 9.0.118
  • WeaknessCWE-200

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

Exposure of HTTP Authentication Header to unexpected hosts during WebSocket authentication vulnerability in Apache Tomcat. This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.21, from 10.1.0-M1 through 10.1.54, from 9.0.2 through 9.0.117, from 8.5.24 through 8.5.100, from 7.0.83 through 7.0.109. Users are recommended to upgrade to version 11.0.22, 10.1.55 or 9.0.118, which fix the issue.

Timeline

dates in UTC
  1. 2026-05-1216:16CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 18:48 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2026-42498?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2026-42498?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD
Apache Tomcat
BranchAffectedFixed in
11.0≥ 11.0.0, < 11.0.2211.0.22
10.1≥ 10.1.0, < 10.1.5510.1.55
9.0≥ 9.0.0, < 9.0.1189.0.118
7.0≥ 7.0.0, ≤ 7.0.109no fix published
8.5≥ 8.5.0, ≤ 8.5.100no fix published

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Vendor advisories

  • CVE-2026-42498 Red Hat Product Security209 products fixed · 45 known affected

    tomcat-coyote: Apache Tomcat: Information disclosure due to HTTP Authentication Header exposure during WebSocket authentication.

    redhat-pki:10/jss.src as a component of Red Hat Certificate System 10 · idm-jss as a component of Red Hat Enterprise Linux 10 · idm-jss-tomcat as a component of Red Hat Enterprise Linux 10 · +42 more

  • RHSA-2026:69259 Red Hat Product Security9 products fixed

    Red Hat Security Advisory: tomcat update

  • RHSA-2026:68651 Red Hat Product Security9 products fixed

    Red Hat Security Advisory: tomcat9 security update

  • RHSA-2026:68677 Red Hat Product Security9 products fixed

    Red Hat Security Advisory: tomcat security update

  • RHSA-2026:68660 Red Hat Product Security9 products fixed

    Red Hat Security Advisory: tomcat security, bug fix, and enhancement update

  • RHSA-2026:68659 Red Hat Product Security9 products fixed

    Red Hat Security Advisory: tomcat security update

11 more advisories

Full record on NVD

Fix

  1. Update Apache Tomcat to 11.0.22 · 10.1.55 · 9.0.118
  2. Vendor fix Red Hat Product Security RHSA-2026:69259 · 9 productsFor details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
  3. Vendor fix Red Hat Product Security RHSA-2026:43401 · 33 productsBefore applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
  4. Vendor fix Red Hat Product Security RHSA-2026:43402 · 1 productBefore applying the update, back up your existing Red Hat JBoss Web Server installation, including all applications and configuration files. The References section of this erratum contains a download link for the update. You must be logged in to download the update.
  5. Vendor fix Red Hat Product Security RHSA-2026:16528 · 21 productsFor details on how to apply this update, which includes the changes described in this advisory, refer to: https://images.redhat.com/

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
none listed
PoC-in-GitHub

Sources

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
Published
2026-05-12
Last Modified
2026-06-17
NVD status
Analyzed

Frequently asked questions

What is CVE-2026-42498?

Exposure of HTTP Authentication Header to unexpected hosts during WebSocket authentication vulnerability in Apache Tomcat. This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.21, from 10.1.0-M1 through 10.1.54, from 9.0.2 through 9.0.117, from 8.5.24 through 8.5.100, from 7.0.83 through 7.0.109. Users are recommended to upgrade to version 11.0.22, 10.1.55 or 9.0.118, which fix the issue.

Is CVE-2026-42498 actively exploited?

Active exploitation of CVE-2026-42498 has not been confirmed. Its EPSS score was 0.6% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-42498?

CVE-2026-42498 has a CVSS v3 base score of 7.3 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L.

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