High 7.5Published Jul 3, 2026

CVE-2026-11352QUIC zero-length UDP datagrams busy-loop

Updated under an hour ago (Oct 26, 2026, 10:50 PM ET)

Does this affect you?

It affects curl and 1 other product. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

Do this next

Start free and add your stack

Free account, 1 product

Every CVE for curl

Exploited in the last 30 days

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.

CVSS: 7.5 HIGH (v3.1, CISA ADP)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness (CWE): CWE-835
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: curl
NVD analysis: Modified
Record last updated: Sep 15, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

curl curl curl:curl (from the name)	from 8.18.0 before 8.20.1	CNA record
haxx curl haxx:curl	from 8.18.0 before 8.21.0	NVD

References

References

https://curl.se/docs/CVE-2026-11352.json	vendor-advisory
https://curl.se/docs/CVE-2026-11352.html	patch, vendor-advisory
https://hackerone.com/reports/3783438	exploit, issue-tracking, third-party-advisory

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.