CVE-2026-26999Public exploitNetwork attack vector

Service interruption via deadline-free TLS handshakes

Published Mar 5, 2026 · Updated Mar 5, 2026

Resource exhaustion in Traefik Proxy 2.11.37 and earlier and 3.6.8 and earlier allows remote attackers to interrupt services via incomplete TLS records. The ServeTCP method in pkg/server/router/tcp/router.go clears the connection deadline before TLS forwarding and retries a failed handshake while ignoring the first error. An unauthenticated client can stop after a partial record, leaving file descriptors and goroutines occupied until enough parallel connections degrade every service on the entrypoint.

CVSS severity7.5
High
EPSS probability0.54%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Resource exhaustion in Traefik Proxy 2.11.37 and earlier and 3.6.8 and earlier allows remote attackers to interrupt services via incomplete TLS records. The ServeTCP method in pkg/server/router/tcp/router.go clears the connection deadline before TLS forwarding and retries a failed handshake while ignoring the first error. An unauthenticated client can stop after a partial record, leaving file descriptors and goroutines occupied until enough parallel connections degrade every service on the entrypoint.

The record

CVE
CVE-2026-26999
Published
Mar 5, 2026
Updated
Mar 5, 2026
Vendor
Traefik Labs
Product
Traefik Proxy
Classifications
CWE-772, CWE-400, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 5, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 5, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 2.11.38
  2. Affected versionversion=< 3.6.9

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Traefik Labs · Traefik Proxyversion=< 2.11.38; version=< 3.6.9

Published CVSS scores

7.5GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-772Missing Release of Resource after Effective Lifetime
CWE-400Uncontrolled Resource Consumption
T1499.004Application or System Exploitation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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