CVE-2026-26998
Traefik: unbounded io.ReadAll on auth server response body causes OOM denial of service(DOS)
Description
Traefik is an HTTP reverse proxy and load balancer. Prior to versions 2.11.38 and 3.6.9, there is a potential vulnerability in Traefik managing the ForwardAuth middleware responses. When Traefik is configured to use the ForwardAuth middleware, the response body from the authentication server is read entirely into memory without any size limit. There is no maxResponseBodySize configuration to restrict the amount of data read from the authentication server response. If the authentication server returns an unexpectedly large or unbounded response body, Traefik will allocate unlimited memory, potentially causing an out-of-memory (OOM) condition that crashes the process. This results in a denial of service for all routes served by the affected Traefik instance. This issue has been patched in versions 2.11.38 and 3.6.9.
INFO
Published Date :
March 5, 2026, 7:16 p.m.
Last Modified :
March 5, 2026, 7:38 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | MEDIUM | [email protected] |
Solution
- Update Traefik to version 2.11.38 or 3.6.9.
- Apply necessary configuration changes if any.
- Restart the Traefik service.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-26998.
| URL | Resource |
|---|---|
| https://github.com/traefik/traefik/releases/tag/v2.11.38 | |
| https://github.com/traefik/traefik/releases/tag/v3.6.9 | |
| https://github.com/traefik/traefik/security/advisories/GHSA-fw45-f5q2-2p4x |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-26998 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-26998
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-26998 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-26998 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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New CVE Received by [email protected]
Mar. 05, 2026
Action Type Old Value New Value Added Description Traefik is an HTTP reverse proxy and load balancer. Prior to versions 2.11.38 and 3.6.9, there is a potential vulnerability in Traefik managing the ForwardAuth middleware responses. When Traefik is configured to use the ForwardAuth middleware, the response body from the authentication server is read entirely into memory without any size limit. There is no maxResponseBodySize configuration to restrict the amount of data read from the authentication server response. If the authentication server returns an unexpectedly large or unbounded response body, Traefik will allocate unlimited memory, potentially causing an out-of-memory (OOM) condition that crashes the process. This results in a denial of service for all routes served by the affected Traefik instance. This issue has been patched in versions 2.11.38 and 3.6.9. Added CVSS V3.1 AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H Added CWE CWE-770 Added Reference https://github.com/traefik/traefik/releases/tag/v2.11.38 Added Reference https://github.com/traefik/traefik/releases/tag/v3.6.9 Added Reference https://github.com/traefik/traefik/security/advisories/GHSA-fw45-f5q2-2p4x