What is CVE-2026-34486?

CVE-2026-34486 is Apache Tomcat: Fix for CVE-2026-29146 allowed bypass of EncryptInterceptor. The supplied enrichment data classifies it as Unclassified mapped to CWE-311 CWE-311; CWE-807 CWE-807.

Which versions are affected?

Affected product and version evidence is listed in the product table above. Current public advisories should be checked for exact version scope before patch targeting is finalized.

Is there active exploitation?

Yes: CISA KEV signal present. If exploitation is not confirmed from current sources, teams should document that status and continue monitoring KEV, vendor, and telemetry updates.

Is there a public exploit?

32 public PoC repositories reported; 3 marked weaponized in current dataset. Public exploit or PoC availability should raise triage priority, especially for exposed or business-critical systems.

How can defenders detect it?

Start with web/proxy/WAF logs, application logs, network IDS/IPS where available. Look for vulnerability-class behavior, product errors, suspicious authentication events, exploit probes, and abnormal process activity based only on evidence that applies to the affected product.

How should teams prioritize it?

Prioritize CVE-2026-34486 using CVSS 7.5, EPSS 99%, KEV status, public PoC status, and asset exposure. Internet-facing, privileged, or business-critical deployments should be handled first.

Are workarounds available?

The supplied mitigation guidance says to apply vendor patches and restrict external exposure until fixed. Fixed-version evidence is listed in the mitigation section above.

Which threat actors are linked publicly?

No public threat actor linkage is confirmed from current sources. Do not attribute exploitation to a threat actor unless the source evidence explicitly supports that linkage.

What should be done in the next 24 hours?

Identify exposed assets running affected vendor/product/version combinations. Treat as emergency remediation because CISA KEV status is present. Search available logs for exploit probes, errors, authentication anomalies, or suspicious child processes matching the vulnerability class. Open remediation tickets with affected assets, owners, evidence status, and detection coverage so decisions are traceable.

CISA KEVhighpublic exploit

CVE-2026-34486

CVE-2026-34486 — Apache Tomcat: Fix for CVE-2026-29146 allowed bypass of EncryptInterceptor

Q: Is it in CISA KEV?

Yes. The supplied enrichment data lists CVE-2026-34486 in CISA KEV with required action: 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.. KEV status should be monitored because it can change after initial disclosure or after exploitation becomes publicly confirmed.

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.

Published Apr 9, 2026Updated Aug 10, 2026Sources: NVD, Apache Software Foundation (CNA), CISA, FIRST EPSS, GitHub, Red Hat (VEX), SOCRadar CTI

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the scoring sources call it.

Exploitation

Confirmed

CISA KEV, listed Aug 4, 2026

EPSS

99%

top of FIRST's scoreset

Affects

Apache

3 products listed

CVSS base

7.5

high

CISA SSVC assessment

Three decision points CISA publishes for the CVEs it assesses · SSVC 2.0.3. A stakeholder decision, not a severity score.

CISA

Exploitation

Active

none · proof-of-concept · active

Automatable

Yes

can an attacker script all four kill-chain steps

Technical impact

Partial

partial · total control of the vulnerable component

Remediation

The vendor's own words where we have them.

Upgrade Apache Tomcat to a fixed release. Apply vendor patches per advisory and restrict external exposure of the affected component until patched.

CISA required action

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.

Federal deadline Aug 7, 2026 — passed 38 days ago

Red Hat VEX · CVE-2026-34486

fixed150affected14not affected62

vendor_fix: Before 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.…

vendor_fix: For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258

First 24 hours

Ordered from the record's own fields — exposure first, because you cannot patch what you have not found.

Identify exposed assets running affected vendor/product/version combinations.
Treat as emergency remediation because CISA KEV status is present.
Search available logs for exploit probes, errors, authentication anomalies, or suspicious child processes matching the vulnerability class.

Affected scope

Vendor, product and version as the advisories word them.

Vendor	Product	Versions	Status
Apache	Apache Tomcat	11.0.20	Vulnerable
Apache	Apache Tomcat	10.1.53	Vulnerable
Apache	Apache Tomcat	9.0.116	Vulnerable

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Availability

None

Confidentiality

High

Integrity

None

Scope

Unchanged

Attack Complexity

Low

Attack Vector

Network

Privileges Req

None

User Interaction

None

Every base score collected

Sources score independently and disagree; each row says who scored it and under which version.

Score	Version	Severity	Expl.	Impact	Source
7.5	CVSS 3.1	high	3.9	3.6	CNA, Red Hat (VEX)

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

What this weakness leads to

MITRE's own consequences and mitigations for the weakness class — the authority's wording, not guidance derived from the CVSS vector.

MITRE

CWE-311 · Missing Encryption of Sensitive Data

Read Application Data
Modify Application Data

Mitigation: 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.

Weakness & attack patterns

CWE-311
CWE-807

Attack patterns reported against this CVE. The ATT&CK techniques below are inferred from its weakness class.

CAPEC-157 · Sniffing AttacksCAPEC-158 · Sniffing Network TrafficCAPEC-204 · Lifting Sensitive Data Embedded in CacheCAPEC-31 · Accessing/Intercepting/Modifying HTTP CookiesCAPEC-37 · Retrieve Embedded Sensitive DataCAPEC-383 · Harvesting Information via API Event MonitoringCAPEC-384 · Application API Message Manipulation via Man-in-the-MiddleCAPEC-385 · Transaction or Event Tampering via Application API ManipulationCAPEC-386 · Application API Navigation RemappingCAPEC-387 · Navigation Remapping To Propagate Malicious ContentCAPEC-388 · Application API Button HijackingCAPEC-477 · Signature Spoofing by Mixing Signed and Unsigned Content

T1040Network Sniffing
T1111Multi-Factor Authentication Interception
T1005Data from Local System

CISA KEV details

CISA lists a CVE here once it has evidence of exploitation against real targets.

CISAThat month →

Listed

Aug 4, 2026

Federal deadline

Aug 7, 2026

passed 38 days ago

Ransomware use

Unknown

CISA records ransomware use only for campaigns it has confirmed, so “Unknown” means unrecorded, not ruled out. The deadline binds US federal agencies; for everyone else it is a date to argue against.

Public exploit

Capability, not use: code existing is a different claim from anyone running it.

Repositories

3 of the 5 sampled are weaponized

Exploit entries

Exploit-DB and CTI exploit indexes

Social mentions

Posts naming this CVE. Attention, not evidence of exploitation — it spikes on disclosure and decays whether or not anything is exploited.

16 more posts on this CVEShowing 5 of 21 · Who is discussing this CVE, and how loudlyUnlock free

Detection

Read off the CVSS vector and the weakness class. Starting points, not rules we have tested.

Prioritize edge telemetry for network-reachable Apache Tomcat.
Monitor for scanner or exploit-pattern traffic after 32 public PoC repositories were reported.

web/proxy/WAF logsapplication logsnetwork IDS/IPS

Timeline

What happened to this CVE, newest first — with the readings a source repeats on a schedule counted underneath rather than listed.

2026
Added · CVSS 3.1 7.5 (AV:N)
Aug 10, 2026 · NVD
Added to CISA KEV catalog
Aug 4, 2026 · CISA
Cve is exploited striga-ai/CVE-2026-34486
May 12, 2026 · SOCRadar CTI
Initial · CVE published
Apr 9, 2026 · NVD

Source activity

Readings a source repeats on a schedule, counted rather than listed.

23×SVRS was changedMay 9, 2026 – Aug 29, 2026 · SOCRadar CTI
7×TweetsMay 12, 2026 – Aug 10, 2026 · SOCRadar CTI
4×Github ReposMay 11, 2026 – Aug 19, 2026 · SOCRadar CTI
2×1 time mentioned on 1 Telegram channelMay 13, 2026 – May 14, 2026 · SOCRadar CTI
1×CVE modified by NIST: CISA KEV details updated.Aug 5, 2026 · SOCRadar CTI

References

25 on the record

lists.apache.org/thread/9510k5p5zdvt9pkkgtyp85mvwxo2qrly
Mailing List, Vendor Advisory, NIST
www.vicarius.io/vsociety/posts/cve-2026-34486-detection-script-rce-on-apache-tomcat
Third Party Advisory, NIST
www.vicarius.io/vsociety/posts/cve-2026-34486-mitigation-script-rce-on-apache-tomcat
Mitigation, Third Party Advisory, NIST
access.redhat.com/errata/RHSA-2026:36787
Third Party Advisory, NIST
access.redhat.com/errata/RHSA-2026:36788
Third Party Advisory, NIST
access.redhat.com/errata/RHSA-2026:36789
Third Party Advisory, NIST
access.redhat.com/errata/RHSA-2026:36790
Third Party Advisory, NIST
access.redhat.com/errata/RHSA-2026:36876
Third Party Advisory, NIST

Coverage

12 stories from the feeds we poll

7 more reports on this CVEShowing 5 of 12 · Vendor research and security press coverageUnlock free

Elsewhere on this site

Apacheevery CVE for this vendor
August 2026what else CISA listed
Unclassifiedsame class
CWE-311other pages naming this weakness

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record1

What should defenders know first?

CVE-2026-34486 is Apache Tomcat: Fix for CVE-2026-29146 allowed bypass of EncryptInterceptor, a high vulnerability affecting Apache Tomcat from Apache Software Foundation. The current evidence lists it in CISA KEV, and the exploit status is: Yes: CISA KEV signal present. Public exploit evidence is: 32 public PoC repositories reported; 3 marked weaponized in current dataset. The affected-version evidence is listed in the key facts and affected products tables. Defenders should first verify whether exposed or business-critical assets run those versions, then apply vendor patches or mitigations, restrict reachable attack surface, and preserve logs for detection review. CVSS 7.5 describes technical severity, while EPSS 99% helps estimate near-term exploit likelihood; neither replaces asset context. Unknown fields should remain explicit in tickets, and threat actor, IOC, victimology, or payload claims should not be added unless a cited source supports them. Monitor CISA KEV, vendor advisories, NVD changes, public PoC repositories, and internal telemetry for update triggers.