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CVE Record

CVE-2026-48020: Traefik StripPrefix Route-Level Auth Bypass via Path Normalization

Traefik is an HTTP reverse proxy and load balancer. Prior to 2.11.48, 3.6.19, and 3.7.3, there is a high severity vulnerability in Traefik's StripPrefix middleware that allows an unauthenticated attacker to bypass route-level authentication and authorization. When a public router matches on a PathPrefix rule and applies the StripPrefix middleware, a request path containing .. or its percent-encoded form %2e%2e can match the public route at routing time and then, after the prefix is stripped and the path is normalized, resolve to a path served by a separate, authenticated router. As a result, an attacker can reach protected backend paths — such as admin or internal configuration endpoints — without satisfying the authentication middleware attached to the protected router. This vulnerability is fixed in 2.11.48, 3.6.19, and 3.7.3.

CriticalCVSS 9.1Not KEV-listedUpdated
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Glexia's TakeAutomated analysiscritical

Security readout for executives and security teams

Plain-English summary

A crafted web request can enter through a public Traefik route and reach a protected backend path without passing that route’s authentication checks. Successful abuse could expose or alter sensitive administrative or internal information. Risk depends on using affected Traefik versions with the specific PathPrefix and StripPrefix routing pattern.

Executive priority

Treat affected, externally reachable configurations as an emergency patching priority because exploitation needs no credentials or user interaction and may compromise sensitive data or settings. Prioritize systems exposing administrative or internal backend paths. Validate configuration exposure before lowering urgency.

Technical view

Traefik evaluates a PathPrefix public router before StripPrefix processing and path normalization. Paths containing parent-directory segments, including their percent-encoded form, can initially match the public router, then normalize to a resource associated with a separate authenticated router. This creates route-level authentication and authorization bypass with high confidentiality and integrity impact.

Likely exposure

Exposure requires an affected Traefik version and a public PathPrefix router using StripPrefix where normalization can resolve requests to protected backend paths. Internet-reachable deployments with adjacent public and authenticated routes deserve immediate review. Deployments without this routing pattern may not be exploitable through this issue.

Exploitation context

The CVSS 3.1 score is 9.1: network-accessible, low complexity, unauthenticated, and requiring no user interaction. The supplied record marks KEV as false, and the source bundle provides no evidence of active exploitation. This does not establish that exploitation is absent.

Researcher notes

The defect combines path traversal semantics with an alternate authentication path: routing authorization occurs against one path interpretation, while the backend target is selected after prefix removal and normalization. Assessment should focus on middleware order, public PathPrefix matches, shared backends, and protected paths. Availability impact is not claimed by the supplied CVSS vector.

Mitigation direction

  • Upgrade Traefik 2.x deployments to 2.11.48 or later.
  • Upgrade Traefik 3.6 deployments to 3.6.19 or later.
  • Upgrade Traefik 3.7 deployments to 3.7.3 or later.
  • Review vendor guidance if immediate upgrading is operationally impossible.
  • Restrict public access to sensitive backend endpoints while remediation is pending.

Validation and detection

  • Inventory all Traefik instances and compare versions with the documented affected ranges.
  • Identify public PathPrefix routers that apply StripPrefix middleware.
  • Map those routers to backends also serving authenticated administrative or internal paths.
  • Confirm upgraded instances report a fixed or later Traefik version.
  • Review proxy and backend logs for abnormal parent-directory or encoded-dot path patterns.
Prepared
Confidence
high
Sources
6

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 · medium confidence lookup

CWE-22: File access and web shell behavior lookup

File traversal and upload weaknesses can lead teams to review file, web shell, execution, and collection telemetry. 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.

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cwe · low confidence lookup

CWE-288: 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.

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cve · low confidence lookup

CVE-2026-48020 mapping review

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

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Vulnerability profileCVE Program record
Severity
Critical
CVSS
9.1 (3.1)
Known Exploited
No
Published

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

2CVSS vectors
5Timeline events
2ADP providers
9Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: yesTechnical 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
9.1CVSS 3.1CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N3.95.2redhat-SADP
7.8CVSS 4.0HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N——GitHub_M

Vulnerability scoring details

Base CVSS 4.0 score

7.8High
CVSS 4.0 vector shape for CVE-2026-48020Attack 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:N/VI:N/VA:N/SC:H/SI:H/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

    Made public.

  3. CVE publishedCVE Program

    The CVE record was published.

  4. ADP timelineredhat-SADP

    Reported to Red Hat.

  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-SADPgithub.com/traefik/traefik: Traefik: Authentication bypass in StripPrefix middleware allows unauthorized access to protected paths
other:Red Hat severity ratingcvssV3_1
  • 2026-06-23T20:00:57.714Z: Reported to Red Hat.
  • 2026-06-23T19:10:31.557Z: Made public.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
traefiktraefik>= 3.7.0-ea.1, < 3.7.3, >= 3.0.0-beta1, < 3.6.19, < 2.11.48Listed
Weakness

CWE details

CWE-22CWE-288

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