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Full vulnerability report · 2026
CVE-2026-73631High confidence

Apache Struts: Shared parsing state in the JSON plugin

Apache Software Foundation · Apache Struts

4.3MediumCVSS 3.1
Recommended action
Scheduled

Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.

Fix not verified
R
Operational reassessment

Published severity in operational context

Open reassessment dashboard →
Published severityMediumOperational priority:Medium, unchanged from published severity.unchanged

Evidence used

  • No CISA KEV confirmation is currently recorded.
  • EPSS is 0.38% for the current model date.

Compensating controls

  • Restrict the affected network interface to trusted sources where business-safe.
  • Monitor vendor guidance and exploitation sources for a material change.

Verification

  1. Confirm that the asset runs Apache Software Foundation Apache Struts and falls inside the recorded affected range.
  2. Recheck the vendor advisory before scheduling a change because no verified fixed version is currently retained.
  3. Validate exposure, authentication requirements and compensating controls in the actual environment.
  4. Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Mitigation target: As exposure requiresRemediation target: Within 365 days

This automated reassessment organises public evidence. It does not know asset exposure, business impact or control effectiveness and does not replace CVSS or a human risk decision.

Optional official sources

National CERT insights
?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

Choose official national sources for this report. Each advisory shows its original language. Your selection is remembered on this device and included in shared links.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current
ENISA EUVD identifier

EUVD-2026-59605

No EUVD known-exploited evidence

ENISA has published the identifier mapping but no EUVD description has been stored yet.

EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
Not supplied in the stored EUVD record
Advisory evidence
No linked advisory details stored yet
Recommended actionScheduled

Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.

Fix not verified
01

What, why and how

Exposure of data element to wrong session vulnerability in the JSON plugin of Apache Struts. Per-request parsing state could be shared across concurrent requests, allowing data associated with one request to become observable in another, and configured parsing limits not to be enforced as intended. Populating actions from a JSON request body is not enabled by default; applications that do not use the JSON plugin are not affected. This issue affects Apache Struts: 7.2.1. Users are recommended to upgrade to version 7.3.0, which fixes the issue.

What

Exposure of data element to wrong session vulnerability in the JSON plugin of Apache Struts. Per-request parsing state could be shared across concurrent requests, allowing data associated with one request to become observable in another, and configured parsing limits not to be enforced as intended. Populating actions from a JSON request body is not enabled by default; applications that do not use the JSON plugin are not affected. This issue affects Apache Struts: 7.2.1. Users are recommended to upgrade to version 7.3.0, which fixes the issue.

Why

The product does not properly synchronize shared data, such as static variables across threads, which can lead to undefined behavior and unpredictable data changes.

How

An attacker operating through a network path may attempt exploitation with low privileges. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

What

Exposure of data element to wrong session vulnerability in the JSON plugin of Apache Struts. Per-request parsing state could be shared across concurrent requests, allowing data associated with one request to become observable in another, and configured parsing limits not to be enforced as intended. Populating actions from a JSON request body is not enabled by default; applications that do not use the JSON plugin are not affected. This issue affects Apache Struts: 7.2.1. Users are recommended to upgrade to version 7.3.0, which fixes the issue.

Why

The product does not properly synchronize shared data, such as static variables across threads, which can lead to undefined behavior and unpredictable data changes.

How

An attacker operating through a network path may attempt exploitation with low privileges. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

02

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
No confirmed evidence

No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.

Public PoC / exploit material
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
None recorded

No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.

Likely attack path
a network path → Unsynchronized Access to Shared Data in a Multithreaded Context → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface
Network
Privileges required
Low: a basic authenticated account is required
User interaction
None
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Unchanged: impact remains within the vulnerable component's security authority
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-567 ↗

CWE-567: Unsynchronized Access to Shared Data in a Multithreaded Context. The product does not properly synchronize shared data, such as static variables across threads, which can lead to undefined behavior and unpredictable data changes.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

Common Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.

AVNetworkAttack vector: The vulnerable component can be reached over a network.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRLowPrivileges required: The attacker needs basic user-level privileges.UINoneUser interaction: No action by another user is required.SUnchangedScope: The security impact remains within the vulnerable component's authority.CLowConfidentiality impact: A successful attack can cause a limited loss.INoneIntegrity impact: No direct loss is represented by this metric.ANoneAvailability impact: No direct loss is represented by this metric.
Post-exploitation / living off the land
No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.
NetworkCWE-567
A

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

BSI · German · WID-SEC-2026-2848Apache Struts: Mehrere Schwachstellen

Ein entfernter, anonymer Angreifer kann mehrere Schwachstellen in Apache Struts ausnutzen, um Sicherheitsmaßnahmen zu umgehen, Daten offenzulegen und zu manipulieren oder um einen Denial of Service zu verursachen.

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2026-028914Apache Software FoundationのApache Strutsにおけるマルチスレッドコンテキスト内の共有データへの非同期アクセスに関する脆弱性

Apache Struts の JSON プラグインにおける誤ったセッションへのデータ要素の露出という脆弱性があります。リクエストごとのパース状態が同時リクエスト間で共有される可能性があり、あるリクエストに関連付けられたデータが別のリクエストで観測可能になるほか、本来意図された通りに設定されたパース制限が適用されない場合があります。JSON リクエストボディからのアクションの補充はデフォルトで有効になっておらず、JSON プラグインを使用していないアプリケーションには影響しません。この問題は Apache Struts バージョン 7.2.1 に影響を及ぼします。ユーザーはこの問題を修正したバージョン 7.3.0 へアップグレードすることが推奨されます。

Official advisory ↗
03

Patch and workaround

Operational remediation based on structured source evidence.

Status
?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Fix not verified
Affected
Apache Struts: 7.2.1
Fixed
No fixed version is explicitly recorded in the structured CVE data.
Action
No verified patch reference is present in the current structured sources. Check the vendor advisory before making a change.
Workaround
No verified workaround is recorded. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.
04

Evidence and provenance

Published 15 Aug 2026 · Last source change 17 Aug 2026, 12:42 UTC · CWE-567 · Unsynchronized Access to Shared Data in a Multithreaded Context

CVE recordCVE.org · 5.2
CVSS sourceCISA ADP
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-08-23
European sourceENISA EUVD · EUVD-2026-59605
Product sourceCNA
Remediation sourceCVE/CNA references
CWE sourceCNA
NVD statusNVD enriched

Core structured fields are present and their contributing authorities are shown above.

Material change intelligence

What changed after publication

View recent updates ↗
  1. Vendor guidanceAuthoritative vendor guidance changed: added vendor advisory: cwiki.apache.org/S2-070.
    Before
    no authoritative guidance recorded
    After
    vendor advisory: cwiki.apache.org/S2-070
    security@apache.org ↗
  2. SeveritySeverity changed from Unknown to Medium.
    Before
    Unknown
    After
    Medium
    CISA ADP ↗
  3. CVSS scoreCVSS score changed from not recorded to 4.3 (CVSS 3.1 · CISA ADP · CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N).
    Before
    not recorded
    After
    4.3 (CVSS 3.1 · CISA ADP · CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N)
    CISA ADP ↗
  4. Catalogue recordCVE added to the BlackTree catalogue.
    CNA ↗
Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
ENISA EUVD · EUVD-2026-59605↗CVE authority or vendor reference↗Official CVE record (CNA and ADP data)↗NVD record↗
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
Free version - for non-commercial use only.CVE-2026-73631 · cve.blacktree.nl