Evidence used
- No CISA KEV confirmation is currently recorded.
- The selected CVSS metric records a network-reachable, unauthenticated path with no user interaction.
- EPSS is 0.24% for the current model date.
BlackTreeCVE IntelligenceFull vulnerability report · 2026
CVE-2026-54763High confidence
Traefik: headerField underscore-variant identity spoofing in BasicAuth / DigestAuth / ForwardAuth
traefik · traefik
Official source article: GitHub GHSA-X677-9FXG-V5C5 ↗. Check the applicable product and release in the original source.
7.8HighCVSS 4.0
Within 7 days
Patch availableHigh technical severity; prioritise exposed affected systems while verifying vendor guidance.
R
Open reassessment dashboard →Operational reassessment
Published severity in operational context
Published severityHigh→Operational priority:High, unchanged from published severity.unchanged
Compensating controls
- Validate the affected product branch and deploy the verified fixed release.
- Restrict the affected network interface to trusted sources where business-safe.
- Monitor vendor guidance and exploitation sources for a material change.
Verification
- Confirm that the asset runs traefik traefik and falls inside the recorded affected range.
- Verify the installed build against the product-specific fixed version after deployment.
- Validate exposure, authentication requirements and compensating controls in the actual environment.
- Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Open-source package ranges3 source-attributed ranges
These OSV and GitHub advisory ranges apply only to the named package and ecosystem. A listed fixed version is not a universal product patch or proof that an update is installed.
| Ecosystem and package | Affected range | First fixed version | Evidence |
|---|---|---|---|
| gogithub.com/traefik/traefik/v2 | <= 2.11.50 | 2.11.51 | GitHub advisory ↗upstream repository advisory · 6 Aug 2026 |
| gogithub.com/traefik/traefik/v3 | <= 3.6.21 | 3.6.22 | GitHub advisory ↗upstream repository advisory · 6 Aug 2026 |
| gogithub.com/traefik/traefik/v3 | >= 3.7.0, <= 3.7.5 | 3.7.6 | GitHub advisory ↗upstream repository advisory · 6 Aug 2026 |
Direct vendor intelligence
2 currentAuthoritative vendor CSAF and VEX advisories
Structured product status and remediation from the issuing vendor. Product-state explanations are always visible; large lists can be searched or downloaded.
CVE-2026-54763 · CSAF 2.0 · revision 3 · finalRed Hat Product Securitytraefik: Traefik: Identity spoofing via improper header handling in authentication middlewares
The vendor explicitly identifies these products or versions as containing the fix.
- registry.redhat.io/devspaces/traefik-rhel9@sha256:38a0acf8e97a7d0c6a4c8d6815321e35df6ad35736a7338267ce9b5adb118662_amd64 as a component of Red Hat OpenShift Dev Spaces 3.30
- registry.redhat.io/devspaces/traefik-rhel9@sha256:8b8f3387a3764beb3d8ad6a027b05f42619ccf33165e733e8dc7b3f135895dc5_ppc64le as a component of Red Hat OpenShift Dev Spaces 3.30
- registry.redhat.io/devspaces/traefik-rhel9@sha256:b338c1060dd859a8747e0812e176ab266d338aea799becd41e48afc50061fb82_s390x as a component of Red Hat OpenShift Dev Spaces 3.30
- registry.redhat.io/devspaces/traefik-rhel9@sha256:ba0aebd6b6b6ceb676b6990d5bd9f3b7efe40cedd9407149da92c55435ef7db6_arm64 as a component of Red Hat OpenShift Dev Spaces 3.30
- Summary
- A flaw was found in Traefik, an HTTP reverse proxy and load balancer. The BasicAuth, DigestAuth, and ForwardAuth middlewares in Traefik do not correctly treat underscore-variant header names. This allows a remote attacker to inject a specially crafted header that bypasses Traefik's security mechanisms. As a result, the attacker can spoof identity or authorization context to the backend, potentially gaining unauthorized access to protected resources.
- Remediation
- Before applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
HPESBNW05119 · CSAF 2.0 · revision 1 · finalHPE NetworkingTraefik Authentication Middleware Header Handling Vulnerability
The vendor explicitly identifies these products as affected by this CVE.
- Private 5G Core
- Summary
- Traefik is an HTTP reverse proxy and load balancer. Prior to v2.11.51, v3.6.22, and v3.7.6, Traefik's BasicAuth, DigestAuth, and ForwardAuth middlewares strip canonical-cased spoofed identity headers before writing Traefik's own value, but do not account for underscore-variant header names, which many backends normalize identically to dashed forms. An attacker able to reach a protected route can inject an underscore-variant header that survives Traefik's stripping and reaches the backend alongside, or on the unauthenticated ForwardAuth authResponseHeaders path instead of, the value Traefik intended to set, spoofing identity or authorization context.
- Remediation
- HPE Aruba Networking recommends upgrading HPE Aruba Networking Private 5G Core to version 1.26.1.3 or later. Software can be downloaded from the HPE Networking Support portal: https://myenterpriselicense.hpe.com/cwp-ui/software.
High technical severity; prioritise exposed affected systems while verifying vendor guidance.
Patch available01
What, why and how
Traefik is an HTTP reverse proxy and load balancer. Prior to v2.11.51, v3.6.22, and v3.7.6, Traefik's BasicAuth, DigestAuth, and ForwardAuth middlewares strip canonical-cased spoofed identity headers before writing Traefik's own value, but do not account for underscore-variant header names, which many backends normalize identically to dashed forms. An attacker able to reach a protected route can inject an underscore-variant header that survives Traefik's stripping and reaches the backend alongside, or on the unauthenticated ForwardAuth authResponseHeaders path instead of, the value Traefik intended to set, spoofing identity or authorization context. This issue is fixed in versions v2.11.51, v3.6.22, and v3.7.6.
What
Traefik is an HTTP reverse proxy and load balancer. Prior to v2.11.51, v3.6.22, and v3.7.6, Traefik's BasicAuth, DigestAuth, and ForwardAuth middlewares strip canonical-cased spoofed identity headers before writing Traefik's own value, but do not account for underscore-variant header names, which many backends normalize identically to dashed forms. An attacker able to reach a protected route can inject an underscore-variant header that survives Traefik's stripping and reaches the backend alongside, or on the unauthenticated ForwardAuth authResponseHeaders path instead of, the value Traefik intended to set, spoofing identity or authorization context. This issue is fixed in versions v2.11.51, v3.6.22, and v3.7.6.
Why
The product does not properly account for differences in case sensitivity when accessing or determining the properties of a resource, leading to inconsistent results.
How
An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.
What
Traefik is an HTTP reverse proxy and load balancer. Prior to v2.11.51, v3.6.22, and v3.7.6, Traefik's BasicAuth, DigestAuth, and ForwardAuth middlewares strip canonical-cased spoofed identity headers before writing Traefik's own value, but do not account for underscore-variant header names, which many backends normalize identically to dashed forms. An attacker able to reach a protected route can inject an underscore-variant header that survives Traefik's stripping and reaches the backend alongside, or on the unauthenticated ForwardAuth authResponseHeaders path instead of, the value Traefik intended to set, spoofing identity or authorization context. This issue is fixed in versions v2.11.51, v3.6.22, and v3.7.6.
Why
The product does not properly account for differences in case sensitivity when accessing or determining the properties of a resource, leading to inconsistent results.
How
An attacker operating through a network path may attempt exploitation without authentication or user interaction. 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 No confirmed evidence
?
Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.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 None recorded
?
Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.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 → Improper Handling of Case Sensitivity → cause the confidentiality, integrity or availability impact described by the vendor
- Attack surface
- Network
- Privileges required
- None: unauthenticated exploitation is possible
- User interaction
- None
- Attack complexity
- Low: no specialised conditions are recorded
- Security boundary
- Not a CVSS 4.0 base metric
- Weakness
?
CWE means Common Weakness Enumeration: a standard category for the underlying weakness. - CWE-178 ↗
CWE-178: Improper Handling of Case Sensitivity. The product does not properly account for differences in case sensitivity when accessing or determining the properties of a resource, leading to inconsistent results.
- CVSS vector
?
CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity. CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/SA:NCommon Vulnerability Scoring System 4.0: 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.ATNoneAttack requirements: No additional deployment or execution condition is required.PRNonePrivileges required: The attacker does not need an account or existing privileges.UINoneUser interaction: No action by another user is required.VCNoneVulnerable-system confidentiality: No direct loss is represented by this metric.VINoneVulnerable-system integrity: No direct loss is represented by this metric.VANoneVulnerable-system availability: No direct loss is represented by this metric.SCHighSubsequent-system confidentiality: A successful attack can cause a major loss.SIHighSubsequent-system integrity: A successful attack can cause a major loss.SANoneSubsequent-system availability: 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.
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. - Patch available
- Fixed
- registry.redhat.io/devspaces/traefik-rhel9@sha256:38a0acf8e97a7d0c6a4c8d6815321e35df6ad35736a7338267ce9b5adb118662_amd64 as a component of Red Hat OpenShift Dev Spaces 3.30
- registry.redhat.io/devspaces/traefik-rhel9@sha256:8b8f3387a3764beb3d8ad6a027b05f42619ccf33165e733e8dc7b3f135895dc5_ppc64le as a component of Red Hat OpenShift Dev Spaces 3.30
- registry.redhat.io/devspaces/traefik-rhel9@sha256:b338c1060dd859a8747e0812e176ab266d338aea799becd41e48afc50061fb82_s390x as a component of Red Hat OpenShift Dev Spaces 3.30
- registry.redhat.io/devspaces/traefik-rhel9@sha256:ba0aebd6b6b6ceb676b6990d5bd9f3b7efe40cedd9407149da92c55435ef7db6_arm64 as a component of Red Hat OpenShift Dev Spaces 3.30
- Action
- Before applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
- 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 6 Jul 2026 · Last source change 8 Jul 2026, 19:42 UTC · CWE-178 · Improper Handling of Case Sensitivity
CVE recordCVE.org · 5.2
CVSS sourceCNA
EPSS source FIRST · tracked since 2026-08-14
?
The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.European sourceENISA EUVD · EUVD-2026-41940
Product sourceCNA
Remediation sourceVendor CSAF · Red Hat Product Security
CWE sourceCNA
NVD statusNVD enriched
Core structured fields are present and their contributing authorities are shown above.
Material change intelligence
View recent updates ↗What changed after publication
- Affected versionsThe structured affected or fixed version information changed.Red Hat Product Security ↗
- Before
- < 2.11.51; >= 3.0.0-beta1, < 3.6.22; >= 3.7.0-ea.1, < 3.7.6 · Fixed: An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
- After
- < 2.11.51; >= 3.0.0-beta1, < 3.6.22; >= 3.7.0-ea.1, < 3.7.6 · Fixed: Before applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
CVE published
Fixed release or patch reference recorded
Fixed release recorded from official guidance
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.