What is CVE-2026-18924?

CVE-2026-18924 is a critical-severity vulnerability in Curl, classified under Use After Free. CVSS score: 9.1/10. Published 2026-09-06.

How severe is CVE-2026-18924?

Critical severity. CVSS v3 base score is 9.1 out of 10.

Use After Free in Curl

CVE-2026-18924

A flaw in libcurl's handling of HTTP/2 Server Push streams, when the parent handle is set to share connections with other handles, can lead to use-after-free in the cleanup process.

Vulnerability class: Use-After-Free

Published 2026-09-06 · last modified 2026-09-15.

CVSS v3 metric

CVSS v3 base score 9.1 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H.

EPSS exploit prediction

EPSS: 0.006 (47.2th percentile), scored 2026-10-22.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 47th percentile — 47.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.009 · newest: 0.006 · change: -0.003

Affected products

Curl — versions 7.70.0, 8.9.0, 8.19.0
Haxx Curl

Weakness classification (CWE)

CWE-416 — Use After Free

References

2499f714-1537-4658-8207-48ae4bb9eae9 (Vendor Advisory)
2499f714-1537-4658-8207-48ae4bb9eae9 (Patch, Vendor Advisory)
2499f714-1537-4658-8207-48ae4bb9eae9 (Exploit, Third Party Advisory, Mitigation)

Frequently asked questions

What is CVE-2026-18924?: CVE-2026-18924 is a critical-severity vulnerability in Curl, classified under Use After Free. CVSS score: 9.1/10. Published 2026-09-06.
How severe is CVE-2026-18924?: Critical severity. CVSS v3 base score is 9.1 out of 10.