Backend connection exhaustion via unbounded HTTP/3 bodies
Published Sep 10, 2026 · Updated Sep 10, 2026
Resource exhaustion in Traefik Proxy 2.8.2 through 2.11.55 and 3.0.0 through 3.7.11 allows remote attackers to hold upstream connections. The HTTP/3 server omits a QUIC-stream read deadline because respondingTimeouts.readTimeout is applied only to TCP connections. HTTP/3 must be enabled; slow request bodies can indefinitely occupy one upstream connection each and exhaust bounded backend pools.
Summary
What happened
Resource exhaustion in Traefik Proxy 2.8.2 through 2.11.55 and 3.0.0 through 3.7.11 allows remote attackers to hold upstream connections. The HTTP/3 server omits a QUIC-stream read deadline because respondingTimeouts.readTimeout is applied only to TCP connections. HTTP/3 must be enabled; slow request bodies can indefinitely occupy one upstream connection each and exhaust bounded backend pools.
The record
- CVE
- CVE-2026-88012
- Published
- Sep 10, 2026
- Updated
- Sep 10, 2026
- Vendor
- Traefik Labs
- Product
- Traefik Proxy
- Classifications
- CWE-770, T1499.004
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Sep 10, 2026CVE publishedPublication date reported by the CVE source.
- Sep 10, 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.
- Affected versionversion=>= 2.8.2, < 2.11.56
- Affected versionversion=>= 3.0.0, < 3.7.12
What conditions does exploitation require?
What is affected?
Published CVSS scores
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.
Weakness, pattern, technique
Public exploit references
- HTTP/3 slow-body timeout reproductionproof of concept · demonstrated
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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