CVE-2026-18924

⛔ critical

Summary

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.

CVSS Score

9.1

Critical

EPSS Score

0.9

Exploit Probability

Published Date

2026-09-06

First Seen: 2026-09-07

📊 Relative Risk Intelligence

This CVE is High Risk - more severe than 87.6% of all 357,695 vulnerabilities in our database.

#44,389

Top 25% most severe

Severity Percentile

🎯 CISA SSVC Assessment Updated: Sep 8, 2026

🔍 Exploitation Status

Poc

Proof-of-concept available

⚙️ Automatable

YES

Can be exploited automatically

💥 Technical Impact

Partial

Limited system impact

🏆 Discovered By

Stephan Zeisberg (Security Research Labs) Daniel Stenberg (remediation developer)

SSVC data provided by CISA

Last Modified 2026-09-15

Source NVD 🔗

CVSS Vector 3.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H

CWE IDs (Weakness Types)

CWE-416

📦 Affected Products 1

Vendor	Product	Status	Affected Versions
haxx	curl	Affected	> 7.44.0 < 8.22.0

🔗 References 3

https://curl.se/docs/CVE-2026-18924.html

Patch Vendor Advisory

https://curl.se/docs/CVE-2026-18924.json

Vendor Advisory

https://hackerone.com/reports/3916059

Exploit Mitigation Third Party Advisory

🔗 Related CVEs 6

CVE ID	Severity	CVSS	EPSS	Summary	Published
CVE-2026-13608	⚠️ high	7.4	0.6	A flaw in the libcurl SASL negotiation for LDAP authentication allows an incomplete handshake sequence to be misinterpre...	2026-09-06
CVE-2026-19931	⛔ critical	9.8	1.2	A flaw in libcurl makes it wrongly reuse an HTTP connection setup for a given hostname using Negotiate authentication, w...	2026-09-06
CVE-2026-80229	⚠️ high	7.5	0.9	When performing transfers via libcurl’s multi interface, pooled TLS connections can outlive their originating easy han...	2026-09-06
CVE-2026-80230	⚠️ high	7.5	0.6	When `CURLOPT_PINNEDPUBLICKEY` is configured alongside options that disable standard peer verification (`CURLOPT_SSL_VER...	2026-09-06
CVE-2026-80231	⚠️ high	7.5	0.9	A flaw in libcurl makes it wrongly reuse an existing HTTPS connection setup for a given hostname even when using a diffe...	2026-09-06
CVE-2026-80255	⚠️ high	7.5	0.7	A `Set-Cookie:` header using tab (horizontal tab, ASCII code 9) instead of space (ascii code 32) immediately before the ...	2026-09-06

These CVEs affect the same products