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No exploitation reportedFix available

CVE-2026-71324

No exploitation reported by the sources we read.

  • Published2026-08-06
  • Fixed in3.7.9 · 3.6.24 · 2.11.53
  • WeaknessCWE-444

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

Traefik is an open source HTTP reverse proxy and load balancer. Prior to 2.11.53, 3.6.24, and 3.7.9, Traefik's default HTTP reverse proxy forwards a plain HTTP/2 or HTTP/3 CONNECT request and its body to an HTTP/1.1 upstream through a shared net/http.Transport. When the upstream answers the CONNECT with a keep-alive non-2xx response and does not drain the body, Traefik returns the desynchronized backend socket to its shared pool and reuses it for other clients. An unauthenticated attacker can use this behavior to make a different client read the attacker's smuggled response, which can include authenticated or private content from another request. The ForwardAuth middleware with forwardBody true and preserveRequestMethod true can re-issue a CONNECT with the buffered body attached, exposing the auth-client pool to the same desynchronization. This issue is fixed in 2.11.53, 3.6.24, and 3.7.9.

Timeline

dates in UTC
  1. 2026-08-0622:18CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 18:48 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2026-71324?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2026-71324?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD · OSV
Traefik
BranchAffectedFixed in
3.7≥ 3.7.0, < 3.7.93.7.9
3.x≥ 3.0.0, < 3.6.243.6.24
3.6< 3.6.243.6.24
2.11< 2.11.532.11.53
traefik/traefik
BranchAffectedFixed in
—all versionsno fix published

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Vendor advisories

  • CVE-2026-71324 Red Hat Product Security1 known affected

    github.com/traefik/traefik: Traefik: Information disclosure via response poisoning in shared backend pool

    devspaces/traefik-rhel9 as a component of Red Hat OpenShift Dev Spaces

Full record on NVD

Fix

  1. Update Traefik to 3.7.9 · 3.6.24 · 2.11.53
  2. Workaround from the vendor Red Hat Product Security CVE-2026-71324 · 1 productTo mitigate this flaw, disable HTTP/2 and HTTP/3 CONNECT request handling at the ingress layer if not required. Alternatively, configure upstream HTTP/1.1 services to forcefully close connections (`Connection: close`) upon returning non-2xx status codes to prevent socket pooling.
  3. No fix available, says the vendor Red Hat Product Security CVE-2026-71324 · 1 productAffected

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
none listed
PoC-in-GitHub

Sources

  • CISA-ADPSSVC decisionnone2026-08-07
  • OpenCVESSVC decisionnone—
  • CNACVSS 4.07read 2026-10-23
  • NVDCVSS 3.19.1read 2026-10-23
  • CNAweakness (CWE)CWE-444read 2026-10-23
  • FIRST EPSSEPSS score1.1 %2026-10-22
  • OSVaffected packages—

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
CVSS 4.0 vector
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/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
Published
2026-08-06
Last Modified
2026-09-16
NVD status
Analyzed

Frequently asked questions

What is CVE-2026-71324?

Traefik is an open source HTTP reverse proxy and load balancer. Prior to 2.11.53, 3.6.24, and 3.7.9, Traefik's default HTTP reverse proxy forwards a plain HTTP/2 or HTTP/3 CONNECT request and its body to an HTTP/1.1 upstream through a shared net/http.Transport. When the upstream answers the CONNECT with a keep-alive non-2xx response and does not drain the body, Traefik returns the desynchronized backend socket to its shared pool and reuses it for other clients. An unauthenticated attacker can use this behavior to make a different client read the attacker's smuggled response, which can include authenticated or private content from another request. The ForwardAuth middleware with forwardBody true and preserveRequestMethod true can re-issue a CONNECT with the buffered body attached, exposing the auth-client pool to the same desynchronization. This issue is fixed in 2.11.53, 3.6.24, and 3.7.9.

Is CVE-2026-71324 actively exploited?

Active exploitation of CVE-2026-71324 has not been confirmed. Its EPSS score was 1.1% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-71324?

CVE-2026-71324 has a CVSS v3 base score of 9.1 (CRITICAL severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N.

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