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CVE Record

CVE-2023-34036: Forwarded header exploit with Spring HATEOAS on WebFlux

Reactive web applications that use Spring HATEOAS to produce hypermedia-based responses might be exposed to malicious forwarded headers if they are not behind a trusted proxy that ensures correctness of such headers, or if they don't have anything else in place to handle (and possibly discard) forwarded headers either in WebFlux or at the level of the underlying HTTP server. For the application to be affected, it needs to satisfy the following requirements: * It needs to use the reactive web stack (Spring WebFlux) and Spring HATEOAS to create links in hypermedia-based responses. * The application infrastructure does not guard against clients submitting (X-)Forwarded… headers.

MediumCVSS 5.3Not KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

Some reactive Spring applications can be tricked into generating incorrect hypermedia links if they accept untrusted Forwarded or X-Forwarded headers. This can affect link integrity in API responses, but the cited CVSS indicates no confidentiality or availability impact.

Executive priority

Treat as a targeted medium-priority fix for affected Spring API services. Prioritize internet-facing WebFlux services that generate HATEOAS links and lack proxy header hardening.

Technical view

CVE-2023-34036 affects Spring HATEOAS in Spring WebFlux applications that create hypermedia links and do not validate, handle, or discard client-supplied forwarded headers. Affected versions listed are 1.5.4 or older, 2.0.4 or older, and 2.1.0.

Likely exposure

Exposure is limited to reactive Spring WebFlux applications using Spring HATEOAS for hypermedia responses without trusted proxy controls or server/WebFlux forwarded-header handling.

Exploitation context

The CVSS vector indicates remote, unauthenticated, low-complexity exploitation with low integrity impact. The source bundle does not show KEV listing or active exploitation evidence.

Researcher notes

The vulnerability maps to CWE-644 and affects integrity of generated links. Evidence is specific to Spring HATEOAS on WebFlux with insufficient forwarded-header safeguards; do not generalize to all Spring applications.

Mitigation direction

  • Check Spring advisory guidance for supported upgrade paths.
  • Ensure only trusted proxies can set forwarded headers.
  • Strip or validate client-supplied Forwarded and X-Forwarded headers.
  • Configure WebFlux or the HTTP server to handle forwarded headers safely.

Validation and detection

  • Inventory Spring HATEOAS versions against the affected version list.
  • Confirm whether the application uses Spring WebFlux, not only Spring MVC.
  • Review proxy and edge configuration for forwarded-header controls.
  • Check hypermedia response generation paths for forwarded-header dependency.
Prepared
Confidence
high
Sources
3

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-644: 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-2023-34036 mapping review

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Vulnerability profileCVE Program record
Severity
Medium
CVSS
5.3 (3.1)
Known Exploited
No
Published

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

1CVSS vectors
0Timeline events
0ADP providers
2Source links

CVSS vector scores

1 official score

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
5.3CVSS 3.1MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N3.91.4Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

5.3Medium
CVSS 3.1 vector shape for CVE-2023-34036Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

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

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
SpringSpring HATEOAS1.5.4 or older, 2.0.4 or older, 2.1.0unaffected
Weakness

CWE details

CWE-644

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

CWE-644 · source CWE mapping

Improper Neutralization of HTTP Headers for Scripting Syntax

Improper Neutralization of HTTP Headers for Scripting Syntax represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

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