CVE-2026-11352
QUIC zero-length UDP datagrams busy-loop
Description
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.
INFO
Published Date :
July 3, 2026, 7:16 a.m.
Last Modified :
July 7, 2026, 6:01 p.m.
Remotely Exploit :
Yes !
Source :
2499f714-1537-4658-8207-48ae4bb9eae9
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | HIGH | 134c704f-9b21-4f2e-91b3-4a467353bcc0 |
Solution
- Update curl or libcurl to the latest version.
- Ensure the QUIC UDP receive function is properly implemented.
- Validate packet budget calculations for QUIC.
- Monitor network traffic for empty datagrams.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-11352.
| URL | Resource |
|---|---|
| https://curl.se/docs/CVE-2026-11352.html | Patch Vendor Advisory |
| https://curl.se/docs/CVE-2026-11352.json | Vendor Advisory |
| https://hackerone.com/reports/3783438 | Exploit Issue Tracking Third Party Advisory |
| https://hackerone.com/reports/3783438 | Exploit Issue Tracking Third Party Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-11352 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-11352
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-11352 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-11352 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Jul. 07, 2026
Action Type Old Value New Value Added CWE CWE-835 Added CPE Configuration OR *cpe:2.3:a:haxx:curl:*:*:*:*:*:*:*:* versions from (including) 8.18.0 up to (excluding) 8.21.0 Added Reference Type curl: https://curl.se/docs/CVE-2026-11352.html Types: Patch, Vendor Advisory Added Reference Type curl: https://curl.se/docs/CVE-2026-11352.json Types: Vendor Advisory Added Reference Type curl: https://hackerone.com/reports/3783438 Types: Exploit, Issue Tracking, Third Party Advisory Added Reference Type CISA-ADP: https://hackerone.com/reports/3783438 Types: Exploit, Issue Tracking, Third Party Advisory -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jul. 06, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Added Reference https://hackerone.com/reports/3783438 Added SSVC {'id': 'CVE-2026-11352', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'poc'}, {'automatable': 'yes'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-07-06T18:26:03.249042Z'} -
New CVE Received by 2499f714-1537-4658-8207-48ae4bb9eae9
Jul. 03, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'curl', 'product': 'curl', 'versions': [{'status': 'affected', 'version': '8.20.0', 'versionType': 'semver', 'lessThanOrEqual': '8.20.0'}, {'status': 'affected', 'version': '8.19.0', 'versionType': 'semver', 'lessThanOrEqual': '8.19.0'}, {'status': 'affected', 'version': '8.18.0', 'versionType': 'semver', 'lessThanOrEqual': '8.18.0'}], 'defaultStatus': 'unaffected'}] Added Description 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. Added Reference https://curl.se/docs/CVE-2026-11352.html Added Reference https://curl.se/docs/CVE-2026-11352.json Added Reference https://hackerone.com/reports/3783438