CVE-2026-11352

HIGH 7.5

QUIC zero-length UDP datagrams busy-loop

CVSS Score

7.5

EPSS Score

0.3%

EPSS Percentile

20th

An issue in curl’s QUIC UDP receive function allows a malicious HTTP/3 server to trigger a remote denial of service against a curl or libcurl client. Because the helper function discards zero-length UDP datagrams before counting them toward the per-call packet budget, a connected QUIC peer can continuously stream empty datagrams to indefinitely stall the client.

Vendor	curl
Product	curl
Published	Jul 3, 2026
Last Updated	Jul 6, 2026

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Affected Versions

curl / curl

8.20.0 ≤ 8.20.0 8.19.0 ≤ 8.19.0 8.18.0 ≤ 8.18.0

References

NVD ↗ CVE.org ↗ EPSS Data ↗

curl.se: https://curl.se/docs/CVE-2026-11352.json curl.se: https://curl.se/docs/CVE-2026-11352.html hackerone.com: https://hackerone.com/reports/3783438

Credits

vectorqueue on hackerone (AntAISecurityLab) Stefan Eissing