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CVE Record

CVE-2026-39852: Quarkus authorization bypass via semicolon path normalization inconsistency

Quarkus is a Java framework for building cloud-native applications. In versions prior to 3.20.6.1, 3.27.3.1, 3.33.1.1, 3.35.1.1, 3.34.7, and 3.35.2, a path normalization inconsistency between the security layer and the routing layer allows unauthenticated or lower-privileged users to bypass HTTP path-based authorization policies. Quarkus's security layer performs authorization checks on the raw URL path which preserves matrix parameters (semicolons), while RESTEasy Reactive's routing layer strips matrix parameters before matching endpoints. An attacker can append a semicolon and arbitrary text to a request URL (e.g., /api/admin;anything) to bypass policies protecting /api/admin while still routing to the protected endpoint. This issue has been fixed in versions 3.20.6.1, 3.27.3.1, 3.33.1.1, 3.35.1.1, 3.34.7, and 3.35.2.

HighCVSS 8.8Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

Affected Quarkus applications may let an unauthenticated or lower-privileged user reach protected HTTP endpoints by altering the requested path. The security check and application router interpret semicolon-containing paths differently, potentially exposing sensitive data or permitting unauthorized changes without credentials or user interaction.

Executive priority

Treat as a high-priority patching issue for reachable applications because exploitation needs no account and can bypass central access controls. Expedite remediation for administrative or sensitive-data routes. Emergency incident response is not justified solely by the supplied evidence because active exploitation is not established.

Technical view

Quarkus security evaluates the raw path, retaining matrix parameters, while RESTEasy Reactive strips them before endpoint matching. Consequently, authorization may evaluate an apparently unprotected path while routing reaches a protected endpoint. The issue is classified as CWE-551 and CWE-863 and carries CVSS 4.0 score 8.8.

Likely exposure

Exposure is most likely in internet-accessible or otherwise untrusted-reachable Quarkus applications running affected versions, using RESTEasy Reactive endpoints protected by HTTP path-based authorization. Applications using unaffected versions or authorization enforced independently at the endpoint may not be exposed; the supplied sources do not enumerate every configuration dependency.

Exploitation context

The attack is remotely reachable, low complexity, requires no privileges or user interaction, and primarily threatens confidentiality. The bundle marks this CVE as absent from KEV and provides no cited evidence of active exploitation. That does not establish that exploitation has never occurred.

Researcher notes

The core flaw is inconsistent canonicalization across authorization and routing boundaries. Review should focus on whether both layers authorize the same normalized path and whether endpoint-level controls provide defense in depth. The CVSS vector indicates high confidentiality impact, low integrity impact, and no stated availability impact. Avoid assuming all Quarkus deployments are exploitable without configuration validation.

Mitigation direction

  • Inventory Quarkus versions and identify applications using RESTEasy Reactive with path-based authorization.
  • Upgrade to an applicable fixed release: 3.20.6.1, 3.27.3.1, 3.33.1.1, 3.34.7, 3.35.1.1, or 3.35.2.
  • Apply the relevant Red Hat erratum when using affected Red Hat-distributed components.
  • Prioritize externally reachable administrative, account, financial, and sensitive-data endpoints.
  • Consult Quarkus or Red Hat guidance if immediate upgrading is operationally constrained.

Validation and detection

  • Confirm deployed Quarkus versions against the affected ranges and fixed-release list.
  • Map path-based authorization policies to their RESTEasy Reactive endpoints.
  • Verify semicolon-bearing path variants cannot reach protected handlers without equivalent authorization.
  • Review access logs for semicolon-containing requests targeting protected paths.
  • Repeat authorization regression tests after upgrading or applying vendor packages.
Prepared
Confidence
high
Sources
4

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-551: 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-863: Authorization and privilege behavior lookup

Authorization weaknesses can support privilege escalation and valid-account review, depending on exploit path. 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
description · low confidence lookup

Privilege behavior lookup

The CVE wording references privilege impact, so privilege escalation and authorization behavior review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.

Open ATT&CK lookup
cve · low confidence lookup

CVE-2026-39852 mapping review

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

Open ATT&CK lookup
Vulnerability profileCVE Program record
Severity
High
CVSS
8.8 (4.0)
Known Exploited
No
Published

Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA: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
2ADP providers
11Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: noTechnical 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
8.8CVSS 4.0HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N——GitHub_M
8.2CVSS 3.1HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H3.94.2redhat-SADP

Vulnerability scoring details

Base CVSS 4.0 score

8.8High
CVSS 4.0 vector shape for CVE-2026-39852Attack VectorAttack ComplexityAttack RequirementsPrivileges RequiredUser InteractionVS ConfidentialityVS IntegrityVS AvailabilitySS ConfidentialitySS IntegritySS Availability

Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Attack Requirements
NonePresent
Privileges Required
NoneLowHigh
User Interaction
NonePassiveActive
VS Confidentiality
HighLowNone
VS Integrity
HighLowNone
VS Availability
HighLowNone
SS Confidentiality
HighLowNone
SS Integrity
HighLowNone
SS Availability
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

    Reported to Red Hat.

  3. ADP timelineredhat-SADP

    Made public.

  4. CVE publishedCVE Program

    The CVE record was published.

  5. CVE updatedCVE Program

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

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
other:ssvc
redhat-SADPio.quarkus:quarkus-vertx-http: io.quarkus:quarkus-vertx-http: Authorization bypass via semicolons in HTTP requests
other:Red Hat severity ratingcvssV3_1
  • 2026-04-13T13:26:46.572Z: Reported to Red Hat.
  • 2026-05-04T00:00:00.000Z: Made public.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
quarkusioquarkus< 3.20.6.1, >= 3.27.3.0, < 3.27.3.1, >= 3.34.0, < 3.34.7, >= 3.35.0, < 3.35.2Listed
Weakness

CWE details

CWE-551CWE-863

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

CWE-551 · source CWE mapping

Incorrect Behavior Order: Authorization Before Parsing and Canonicalization

Incorrect Behavior Order: Authorization Before Parsing and Canonicalization represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

Open CWE intelligenceSame-CWE CVEs
CWE-863 · source CWE mapping

Incorrect Authorization

Incorrect Authorization represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

Open CWE intelligenceSame-CWE CVEs