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CVE Record

CVE-2026-29146: Apache Tomcat: EncryptInterceptor vulnerable to padding oracle attack by default

Padding Oracle vulnerability in Apache Tomcat's EncryptInterceptor with default configuration. This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.18, from 10.0.0-M1 through 10.1.52, from 9.0.13 through 9..115, from 8.5.38 through 8.5.100, from 7.0.100 through 7.0.109. Users are recommended to upgrade to version 11.0.19, 10.1.53 and 9.0.116, which fixes the issue.

HighCVSS 7.5Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

Apache Tomcat’s EncryptInterceptor can reveal protected information through differences in how malformed encrypted data is handled. A remote, unauthenticated attacker may exploit this padding oracle to recover confidential data. Risk applies to deployments using the interceptor’s vulnerable default configuration, not automatically to every Tomcat server.

Executive priority

Treat as a high-priority confidentiality issue where EncryptInterceptor is enabled and reachable from untrusted networks. Identify exposed deployments immediately and schedule rapid upgrades. Lower priority only after evidence shows the interceptor is absent, the affected path is inaccessible, or the installed vendor package is remediated.

Technical view

CVE-2026-29146 is a network-accessible padding oracle in EncryptInterceptor. The supplied CVSS 3.1 score is 7.5: low complexity, no privileges or user interaction, with high confidentiality impact but no stated integrity or availability impact. Affected branches include Tomcat 11, 10.1, 9, 8.5, and 7 within the supplied ranges.

Likely exposure

Prioritize internet-reachable or untrusted-network Tomcat deployments using EncryptInterceptor with its default configuration. Version presence alone does not prove exploitability; confirm that the interceptor is configured and exposed. The bundle names affected ranges through 11.0.18, 10.1.52, 9.0.115, 8.5.100, and 7.0.109.

Exploitation context

The CVSS vector indicates remote, unauthenticated exploitation without user interaction. However, the bundle marks KEV false and provides no evidence of active exploitation or a public exploit. Treat exploitation status as unconfirmed while addressing exposed vulnerable configurations promptly.

Researcher notes

The weakness is classified under CWE-1240, CWE-209, and CWE-642. Assessment should distinguish observable oracle behavior from mere version detection, without testing against production destructively. The supplied description contains a typographical version string for the 9.x upper bound; the stated fixed release is 9.0.116.

Mitigation direction

  • Upgrade to Tomcat 11.0.19, 10.1.53, or 9.0.116, as appropriate.
  • For Tomcat 8.5 or 7, check Apache guidance and migrate to a named fixed, supported branch.
  • Apply applicable Red Hat security updates when using Red Hat-packaged Tomcat components.
  • Restrict untrusted network access to affected cluster communication paths until remediation is complete.

Validation and detection

  • Inventory Tomcat versions across hosts, containers, images, and bundled applications.
  • Inspect Tomcat cluster configuration to determine whether EncryptInterceptor is enabled.
  • Confirm upgraded instances report 11.0.19, 10.1.53, 9.0.116, or a vendor-remediated package.
  • Verify network controls prevent untrusted access to affected cluster communication paths.
  • Review vendor advisories for later corrections or product-specific remediation details.
Prepared
Confidence
high
Sources
6

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cwe · low confidence lookup

CWE-1240: Exact CWE lookup

Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

Open ATT&CK lookup
cwe · medium confidence lookup

CWE-209: Information exposure and cloud metadata lookup

Information exposure and SSRF weaknesses can make discovery, cloud metadata, and credential material review relevant. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

Open ATT&CK lookup
cwe · low confidence lookup

CWE-642: Exact CWE lookup

Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

Open ATT&CK lookup
cve · low confidence lookup

CVE-2026-29146 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

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Vulnerability profileCVE Program record
Severity
High
CVSS
7.5 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

2CVSS vectors
5Timeline events
3ADP providers
20Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: yesTechnical Impact: partial

CVSS vector scores

2 official scores

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
7.5CVSS 3.1HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N3.93.6CISA-ADP
7.5CVSS 3.1HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N3.93.6redhat-SADP

Vulnerability scoring details

Base CVSS 3.1 score

7.5High
CVSS 3.1 vector shape for CVE-2026-29146Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. ADP timelineredhat-SADP

    Made public.

  3. CVE publishedCVE Program

    The CVE record was published.

  4. ADP timelineredhat-SADP

    Reported to Red Hat.

  5. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CVECVE Program Container
CISA-ADPCISA ADP Vulnrichment
cvssV3_1other:ssvc
redhat-SADPApache Tomcat: Apache Tomcat: Information disclosure via Padding Oracle vulnerability in EncryptInterceptor
other:Red Hat severity ratingcvssV3_1
  • 2026-04-09T20:01:03.123Z: Reported to Red Hat.
  • 2026-04-09T19:21:57.289Z: Made public.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
Apache Software FoundationApache Tomcat11.0.0-M1, 10.0.0-M1, 9.0.13, 8.5.38, 7.0.100unaffected
Weakness

CWE details

CWE-1240CWE-209CWE-642

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.