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No exploitation reportedFix available

CVE-2026-55956

No exploitation reported by the sources we read.

  • Published2026-06-29
  • Fixed in11.0.23 · 10.1.56 · 9.0.119
  • WeaknessCWE-285

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

Improper Authorization vulnerability in Apache Tomcat leads to security constraints specified for the default servlet ignoring any method or method omission configured as part of the constraint. This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.22, from 10.1.0-M1 through 10.1.55, from 9.0.0.M1 through 9.0.118, from 8.5.0 through 8.5.100, from 7.0.0 through 7.0.109. Other versions that have reached end of support may also be affected. Users are recommended to upgrade to version 11.0.23, 10.1.56 or 9.0.119, which fix the issue.

Timeline

dates in UTC
  1. 2026-06-2921:16CVE 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-2026-55956?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2026-55956?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, < 11.0.2311.0.23
10.1≥ 10.1.0, < 10.1.5610.1.56
9.0< 9.0.1199.0.119

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

  • 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

  • RHSA-2026:68678 Red Hat Product Security9 products fixed

    Red Hat Security Advisory: tomcat security update

  • RHSA-2026:68679 Red Hat Product Security9 products fixed

    Red Hat Security Advisory: tomcat security update

6 more advisories

Full record on NVD

Fix

  1. Update Apache Tomcat to 11.0.23 · 10.1.56 · 9.0.119
  2. Vendor fix Red Hat Product Security RHSA-2026:68651 · 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. Workaround from the vendor Red Hat Product Security RHSA-2026:68651 · 9 productsReview your application's web.xml file. Ensure security constraints explicitly deny unauthorized users by path, rather than relying strictly on filtering specific HTTP methods (like GET or POST).

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:N
Published
2026-06-29
Last Modified
2026-07-02
NVD status
Analyzed

Frequently asked questions

What is CVE-2026-55956?

Improper Authorization vulnerability in Apache Tomcat leads to security constraints specified for the default servlet ignoring any method or method omission configured as part of the constraint. This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.22, from 10.1.0-M1 through 10.1.55, from 9.0.0.M1 through 9.0.118, from 8.5.0 through 8.5.100, from 7.0.0 through 7.0.109. Other versions that have reached end of support may also be affected. Users are recommended to upgrade to version 11.0.23, 10.1.56 or 9.0.119, which fix the issue.

Is CVE-2026-55956 actively exploited?

Active exploitation of CVE-2026-55956 has not been confirmed. Its EPSS score was 0.7% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-55956?

CVE-2026-55956 has a CVSS v3 base score of 6.5 (MEDIUM severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N.

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