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Fencer Intel
medium 5.8

CVE-2026-41181 json

Traefik: Errors middleware forwards Authorization and Cookie headers to separate error page service

published 6mo ago modified 2mo ago also EUVD-2026-30557 , GHSA-p6hg-qh38-555r , GO-2026-5532

cvss
5.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 39%
public exploits
0
none known

Summary

Traefik is an HTTP reverse proxy and load balancer. Prior to 2.11.44, 3.6.15, and 3.7.0-rc.3, there is an information disclosure vulnerability in Traefik's errors (custom error pages) middleware. When the backend returns a response matching the configured status range, the middleware forwards the original request's complete header set, including Authorization, Cookie, and other authentication material, to the separate error page service rather than only the minimal context needed to render the error page. This behavior is undocumented: the documentation states only that Host is forwarded by default, so operators are not warned that sensitive credentials are shared across service boundaries. Deployments using the errors middleware with a distinct error page service may inadvertently expose end-user credentials to infrastructure that was not intended to receive them. This vulnerability is fixed in 2.11.44, 3.6.15, and 3.7.0-rc.3.

Patch / fix

  • go github.com/traefik/traefik/v2 2.11.44
  • go github.com/traefik/traefik/v3 3.6.15, 3.7.0-rc.3
  • traefik traefik 2.11.43, 3.6.14, 3.7.0-rc.3
  • govulncheck-vulndb SLES for SAP applications 16.0, SLES 16.0 0.0.20260827T195228-160000.1.1

suse advisories SUSE-SU-2026:23625-1

  • govulncheck-vulndb openSUSE Leap 16.0 0.0.20260827T195228-160000.1.1
  • traefik openSUSE Tumbleweed 3.6.16-1.1
  • traefik2 openSUSE Tumbleweed 2.11.45-1.1

opensuse advisories openSUSE-SU-2026:21761-1openSUSE-SU-2026:10713-1openSUSE-SU-2026:10714-1

Is CVE-2026-41181 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

Check with Fencer

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-41181 updated cvss 5.8

traefik: Traefik: Information disclosure via errors middleware exposing user credentials

  • Red Hat OpenShift Dev Spaces devspaces/traefik-rhel9
    affected: no fix available “Fix deferred”

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
5mo ago

Exploit prediction

0.45% chance of exploitation in the next 30 days, higher than 39% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • github.com https://github.com/traefik/traefik/security/advisories/GHSA-p6hg-qh38-555r referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 4.0 6.9 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:N/SA:N
CNA 4.0 6.9 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
NVD 3.1 5.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N

Affected packages

ecosystem package affected fixed in
go github.com/traefik/traefik/v2
<2.11.44
2.11.44
go github.com/traefik/traefik/v3
<3.6.15
>=3.7.0-rc.0, <3.7.0-rc.3
>=3.7.0-rc.1, <3.7.0-rc.3
3.6.15
3.7.0-rc.3
go github.com/traefik/traefik
all versions
 no fix listed

Affected products

  • traefik traefik

Classification

Weakness
  • CWE-201 Insertion of Sensitive Information Into Sent Data

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.