VulnerabilityPublished 9 Apr 2026Updated 7 Aug 2026

CVE-2026-34486: Tomcat8 · Missing Encryption of Sensitive Data vulnerability in Apache Tomcat due to the fix for

Affects Apache tomcat8Source GCVE Database

Mentioned vulnerabilities

CVE-2026-29146

Authoritative record:CVE-2026-34486· High 7.5

Exploited in the wild · KEV due 7 Aug 2026 · public detection template (Nuclei) · 98% EPSS · fixed in 11.0.21 : patch Apache tomcat8 now.

Data as of 26 Oct 2026, 14:05 UTC

CVSS 3.1 base score

7.5High

How severe the flaw is on the 0–10 CVSS scale.

KEV deadline: 7 Aug 2026 US federal agencies must patch by this date; a sensible deadline for everyone else. Other KEV due dates
EPSS: 98.5% chance of exploitation in 30 days – higher than 99% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 11.0.21

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: High
Integrity: None
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

t = 0 is the CVE’s publication on cve.org

Disclosed: evidence found.
CVE published 9 Apr 2026
Detectable: evidence found.
nuclei template: Apache Tomcat Tribes EncryptInterceptor Bypass - Remote Code Execution
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: evidence found.
Listed in CISA KEV 117 days after disclosure
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

CVE ID reserved
by Apache Software Foundation
30 Mar 202607:57 UTC, 10 days before disclosure
CVE published
on cve.org
9 Apr 202619:35 UTC, t = 0
In Threat Radar
record ingested
9 Apr 202620:06 UTC, 31 minutes after disclosure
Added to CISA KEV (opens in a new tab)
exploitation confirmed
4 Aug 2026, 117 days after disclosure
KEV remediation due
US federal deadline
7 Aug 2026, 120 days after disclosure

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), CISA KEV (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.

Affected software

Product	Affected	Fixed in
Ubuntu Pro 18.04 LTStomcat8`pkg:deb/ubuntu/tomcat8?arch=source&distro=esm-apps/bionic`Other threats	Affected 8.5.21-1ubuntu1 – 8.5.39-1ubuntu1~18.04.3+esm6 16 affected builds	Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

Description

Missing Encryption of Sensitive Data vulnerability in Apache Tomcat due to the fix for CVE-2026-29146 allowing the bypass of the EncryptInterceptor. This issue affects Apache Tomcat: 11.0.20, 10.1.53, 9.0.116. Users are recommended to upgrade to version 11.0.21, 10.1.54 or 9.0.117, which fix the issue.

CWE-311Missing Encryption of Sensitive Data (opens in a new tab)
Class weaknessLikelihood of exploit: HighOWASP Top 10 A06:2025: Insecure Design (opens in a new tab)
The product does not encrypt sensitive or critical information before storage or transmission.
MITRE discourages mapping vulnerabilities to this broad entry; the root cause is usually a more specific weakness.
Requirements
Clearly specify which data or resources are valuable enough that they should be protected by encryption. Require that any transmission or storage of this data/resource should use well-vetted encryption algorithms.
Architecture and Design
Ensure that encryption is properly integrated into the system design, including but not necessarily limited to: Encryption that is needed to store or transmit private data of the users of the system; Encryption that is needed to protect the system itself from unauthorized disclosure or tampering
Architecture and Design · Libraries or Frameworks
When there is a need to store or transmit sensitive data, use strong, up-to-date cryptographic algorithms to encrypt that data. Select a well-vetted algorithm that is currently considered to be strong by experts in the field, and use well-tested implementations.
OWASP Cheat Sheets
Abuse Case (opens in a new tab)
User Privacy Protection (opens in a new tab)
Secure Design Principles (opens in a new tab)
OWASP ASVS 4.0.3
V6.1.3 (opens in a new tab)
V6.1.2 (opens in a new tab)
V6.1.1 (opens in a new tab)
Attack patterns
Sniffing Attacks (opens in a new tab)
Sniffing Network Traffic (opens in a new tab)
Lifting Sensitive Data Embedded in Cache (opens in a new tab)
Accessing/Intercepting/Modifying HTTP Cookies (opens in a new tab)
Retrieve Embedded Sensitive Data (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

Timeline

What to do

Affected software

Description

Public exploits and detectiona Nuclei detection template

WeaknessesCWE-311

Technical details

References

Community reviews

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