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TI-2026-83076 Aliases CVE-2026-119574GHSA-r4c9-879g-3g2v

Data race in Traefik FastProxy enables unauthenticated denial of service

Priority LOW 35CWE-567Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Attack requirements
Present
Impact type
—
Confidentiality · integrity · availability
None · None · High
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA.

Summary

Traefik from 3.2.0 before 3.7.15 contains a data race in the experimental FastProxy component (CWE-567). An unauthenticated remote attacker can repeatedly open and abort upgraded HTTP/1 connections such as WebSocket, corrupting a shared buffer and triggering an unrecovered panic that terminates the process, causing denial of service.

Written with Claude Haiku 5.5 from the sources below · 2026-11-06

Description from the CNA

Traefik from 3.2.0 before 3.7.15 contains a data race in the experimental FastProxy that allows unauthenticated attackers to crash the process by abusing HTTP/1 protocol upgrades. Attackers can repeatedly open and abort upgraded connections such as WebSocket, corrupting the unsynchronized shared bufio.Reader and triggering an unrecovered panic that terminates Traefik.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00284 21st percentileScored 2026-11-07
Fix Fixed traefik (traefik): 3.7.15

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
traefiktraefik3.2.0 to before 3.7.153.7.15Patch availableCNA
  • traefik Vendortraefik Affected 3.2.0 to before 3.7.15 Fixed in 3.7.15 Patch available CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:traefik:traefik:*:*:*:*:*:*:*:*3.2.0 to before 3.7.15Vulnerabletraefik
  • cpe:2.3:a:traefik:traefik:*:*:*:*:*:*:*:* Versions 3.2.0 to before 3.7.15 Vulnerable ·traefik

Remediation

Upgrade Traefik to version 3.7.15, which fixes this issue for affected versions from 3.2.0 before 3.7.15.

Written with Claude Haiku 5.5 from the sources below · 2026-11-06

  • Fix · CNA traefik (traefik) Fixed in 3.7.15

Fixed in the same release

Records fixed by the same vendor advisory or release, as the CNA lists them.

  • Release ·

    traefik 3.7.15

    3 records Highest priority Priority LOW 3 LOW

    Other records, highest priority first

    • TI-2026-83074 Authentication bypass in Traefik Ingress NGINX provider disables mTLSPriority LOW 30
    • TI-2026-83075 Authorization bypass in Traefik Kubernetes Ingress NGINX providerPriority LOW 11
    Show all 3 records →

Vendor assessments

Red Hat

Red Hat's page for this CVE →

Not affected: 1 product
  • Red Hat

Timeline

  1. 2026-10-30 Threatist record created from CVE-2026-119574
  2. 2026-10-30 CISA SSVC decision points changed
  3. 2026-10-30 Priority changed: MEDIUM → LOW
  4. 2026-10-30 Alias added: GHSA-r4c9-879g-3g2v
  5. 2026-11-06 Affected versions changed · Red Hat
  6. 2026-11-06 CVSS score added · Red Hat

References

Patch 1

  • TI-2023-23979 The HTTP/2 protocol allows a denial of service (server resource consumption) because… KEVCVSS 3.1HIGH 7.5
  • TI-2023-25774 Uncontrolled Resource Consumption in Traefik CVSS 3.1HIGH 7.5
  • TI-2025-40914 Traefik doesn't Prevent Path Normalization Bypass in Router + Middleware Rules CVSS 4.0MEDIUM 6.9
  • TI-2022-07529 Authorization header displayed in the debug logs CVSS 3.1MEDIUM 6.5
  • TI-2024-30459 HTTP client can remove the X-Forwarded headers in Traefik CVSS 3.1CRITICAL 9.8
  • TI-2026-60261 Traefik v3.7.0 Authentication Bypass via from-to-www-redirect CVSS 4.0CRITICAL 9.3
See all 83 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences