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Medium 2 vendors · 2 advisories

CVE-2026-55955: Apache Tomcat: EncryptInterceptor not protected against replay attacks

CVE-2026-55955 key facts

CISA KEV
Not listed (catalogue checked )
Highest advisory rating
Medium
CVSS base score
6.5 (NetApp), 4.2 (Red Hat)
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N · base score 6.5, scored by CISA-ADPAttack vector: network. Attack complexity: low. Privileges required: none. User interaction: none. Scope: unchanged. Confidentiality impact: low. Integrity impact: low. Availability impact: none.
Weakness
  • CWE-287 Improper Authentication
EPSS
0.44% chance of exploitation in the next 30 days (38th percentile). FIRST EPSS, .
CISA SSVC
Exploitation: none observed. Automatable: no. Technical impact: partial. CISA, .
Fixed releases
  • Red Hat: 11.0.23, 10.1.56, 9.0.119, tomcat9-1:9.0.120-1.el10_2, tomcat9-1:9.0.120-1.el10_0, tomcat-1:9.0.120-1.el8_10 and 17 more in the advisory
Vendor advisories
2 from NetApp, Red Hat
Assigned by
apache (CNA)
CVE record published
Listed by VulniPulse
Record changed

Ratings, versions and fixes are quoted from the vendor advisories that cover only CVE-2026-55955; each belongs to its advisory, not to every product listed. How records are collected and checked.

Description

Improper Authentication vulnerability in Apache Tomcat allowed a replay attack against the EncryptionInterceptor in the cluster component. This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.22, from 10.1.0-M1 through 10.1.55, from 9.0.13 through 9.0.18, from 8.5.38 through 8.5.100, from 7.0.100 through 7.0.109. Users are recommended to upgrade to version 11.0.23, 10.1.56, 9.0.119, which fixes the issue.

Text from the CVE.org record (apache).

How do I fix CVE-2026-55955?

Upgrade to a fixed release named by the vendor:

  • Red Hat: 11.0.23, 10.1.56, 9.0.119, tomcat9-1:9.0.120-1.el10_2, tomcat9-1:9.0.120-1.el10_0, tomcat-1:9.0.120-1.el8_10
  • This vulnerability only affects Tomcat deployments using the EncryptionInterceptor for Tribes cluster communication. Deployments that do not use Tomcat clustering or do not configure the EncryptionInterceptor are not affected. Ensure cluster communication channels are restricted to trusted, isolated networks. (Red Hat)

Vendor advisories for CVE-2026-55955

NetApp

1 advisory
  • Advisory severityMedium6.5

    Medium [CVE-2026-55955] Apache Tomcat Vulnerability in NetApp Products

    NTAP-20260703-0015Source published Source updated

    Apache Tomcat versions 11.0.0-M1 through 11.0.22, 10.1.0-M1 through 10.1.55, and 9.0.13 through 9.0.118 are susceptible to a vulnerability which when successfully exploited could lead to disclosure of sensitive information or addition or modification of data. NetApp reports that one or more additional products remain under investigation; review the canonical advisory for current status. NetApp states there is no workaround available at this time.

    Affected products in this advisory
    No product details extracted. Check the source bulletin.
    Source-reported affected versions
    • 11.0.0
    • 11.0.22
    • 10.1.0
    • 10.1.55

    2 more entries in the full advisory.

    Source-reported fixed versions
    No fixed-version detail extracted. This does not mean no fix exists.
    Mitigation guidance
    No mitigation guidance extracted; consult the source.
    Full advisory and evidenceOpen source bulletin

Red Hat

1 advisory
  • Advisory severityMedium4.2

    Medium [CVE-2026-55955] Replay attack via improper authentication in EncryptionInterceptor

    CVE-2026-55955Source published Source updated

    Improper Authentication vulnerability in Apache Tomcat allowed a replay attack against the EncryptionInterceptor in the cluster component. This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.22, from 10.1.0-M1 through 10.1.55, from 9.0.13 through 9.0.18, from 8.5.38 through 8.5.100, from 7.0.100 through 7.0.109. Users are recommended to upgrade to version 11.0.23, 10.1.56, 9.0.119, which fixes the issue. This could lead to unauthorized access or manipulation of data within the cluster component. A flaw was found in Apache Tomcat's EncryptionInterceptor used for Tribes cluster communication. Exploitation requires the EncryptionInterceptor to be configured for Tomcat clustering, which is a non-default configuration, and the attacker must have access to the cluster network to…

    Affected products in this advisory
    • Red Hat Enterprise Linux 10.0 Extended Update Support
    • Red Hat Enterprise Linux 8.8 Telecommunications Update Service
    • Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions
    • Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions

    9 more entries in the full advisory.

    Source-reported affected versions
    • 11.0.0
    • 11.0.22
    • 10.1.0
    • 10.1.55

    6 more entries in the full advisory.

    Source-reported fixed versions
    • 11.0.23
    • 10.1.56
    • 9.0.119
    • tomcat9-1:9.0.120-1.el10_2

    19 more entries in the full advisory.

    Mitigation guidance
    • This vulnerability only affects Tomcat deployments using the EncryptionInterceptor for Tribes cluster communication. Deployments that do not use Tomcat clustering or do not configure the EncryptionInterceptor are not affected. Ensure cluster communication channels are restricted to trusted, isolated networks.
    Full advisory and evidenceOpen source bulletin

References

Timeline

  1. CVE record published
  2. CVE record last updated
  3. First vendor advisory listed by VulniPulse

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