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CVE Record

CVE-2026-29054: Traefik: lowercase `Connection` tokens can delete traefik-managed forwarded identity headers (for example, `X-Real-Ip`)

Traefik is an HTTP reverse proxy and load balancer. From version 2.11.9 to 2.11.37 and from version 3.1.3 to 3.6.8, there is a potential vulnerability in Traefik managing the Connection header with X-Forwarded headers. When Traefik processes HTTP/1.1 requests, the protection put in place to prevent the removal of Traefik-managed X-Forwarded headers (such as X-Real-Ip, X-Forwarded-Host, X-Forwarded-Port, etc.) via the Connection header does not handle case sensitivity correctly. The Connection tokens are compared case-sensitively against the protected header names, but the actual header deletion operates case-insensitively. As a result, a remote unauthenticated client can use lowercase Connection tokens (e.g. Connection: x-real-ip) to bypass the protection and trigger the removal of Traefik-managed forwarded identity headers. This issue has been patched in versions 2.11.38 and 3.6.9.

HighCVSS 7.5Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

Some vulnerable Traefik versions can be tricked into removing identity headers that Traefik normally sets for backend services. This can break assumptions about client IP, host, or forwarding metadata. The main risk is incorrect trust, authorization, routing, audit, or rate-limit decisions in systems behind Traefik.

Executive priority

Treat this as a high-priority edge proxy update. It is not reported as actively exploited in the supplied sources, but vulnerable deployments can undermine controls that depend on trusted client identity metadata.

Technical view

CVE-2026-29054 is a CWE-178 case-sensitivity flaw in Traefik HTTP/1.1 Connection header handling. Protected forwarded headers are compared case-sensitively, while deletion is case-insensitive, allowing unauthenticated clients to cause removal of Traefik-managed X-Forwarded and X-Real-IP style headers. Patched versions are 2.11.38 and 3.6.9.

Likely exposure

Exposure is likely where Traefik versions 2.11.9 through 2.11.37 or 3.1.3 through 3.6.8 proxy HTTP/1.1 traffic, especially for internet-facing services whose backends trust forwarded identity headers for policy, logging, routing, rate limiting, or security decisions.

Exploitation context

The bundle does not show CISA KEV listing or cited evidence of active exploitation. The advisory describes remote unauthenticated reachability and low attack complexity. Practical impact depends on whether downstream services make security-relevant decisions from headers Traefik manages.

Researcher notes

Focus assessment on trust boundaries behind Traefik. The vulnerability is not direct data disclosure or availability loss; the CVSS integrity impact reflects possible manipulation of backend context by removing proxy-managed forwarding headers.

Mitigation direction

  • Upgrade Traefik 2.x deployments to 2.11.38 or later.
  • Upgrade Traefik 3.x deployments to 3.6.9 or later.
  • For Red Hat packages, follow RHSA-2026:10175 and related product guidance.
  • If patching is delayed, consult vendor guidance before relying on compensating controls.

Validation and detection

  • Inventory all Traefik instances and record exact running versions.
  • Confirm no deployment remains on affected 2.11.9-2.11.37 or 3.1.3-3.6.8 versions.
  • Identify backend services that trust X-Real-IP or X-Forwarded headers.
  • Check logs for unexpected Connection header values naming forwarded identity headers.
  • After upgrading, confirm downstream services still receive expected forwarded identity metadata.
Prepared
Confidence
high
Sources
7

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-178: 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-2026-29054 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
High
CVSS
7.5 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/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
8Source 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
7.5CVSS 3.1HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N3.93.6GitHub_M
7.5CVSS 3.1HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N3.93.6redhat-SADP

Vulnerability scoring details

Base CVSS 3.1 score

7.5High
CVSS 3.1 vector shape for CVE-2026-29054Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

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

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: Information disclosure due to case-insensitive Connection header processing
other:Red Hat severity ratingcvssV3_1
  • 2026-03-05T19:01:04.119Z: Reported to Red Hat.
  • 2026-03-05T16:18:49.230Z: Made public.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
traefiktraefik>= 2.11.9, < 2.11.38, >= 3.1.3, < 3.6.9Listed
Weakness

CWE details

CWE-178

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

CWE-178 · source CWE mapping

Improper Handling of Case Sensitivity

Improper Handling of Case Sensitivity represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

Open CWE intelligenceSame-CWE CVEs