CVE-2026-18924 - Vulnerability Details

Description

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.

Published: 2026-09-06

Score: 9.1 Critical

EPSS: < 1% Very Low

KEV: No

Impact:

Action:

Analysis

Analysis and contextual insights are available on OpenCVE Cloud.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

curl

unaffected

Version	Status	Constraints
`7.44.0`	affected	< 8.14.2
`8.15.0`	affected	< 8.16.1
`8.17.0`	affected	< 8.20.1
`8.21.0`	affected	< 8.22.0

curl

unaffected

Version	Status	Constraints
`ea7134ac874a66107e54ff93657ac565cf2ec4aa`	affected	< 90325ff0444cbdff368bda5d26d6405a0bb6ee43

curl

unaffected

Version	Status	Constraints
`8.21.0`	affected	—
`8.20.0`	affected	—
`8.19.0`	affected	—
`8.18.0`	affected	—
`8.17.0`	affected	—
`8.16.0`	affected	—
`8.15.0`	affected	—
`8.14.1`	affected	—
`8.14.0`	affected	—
`8.13.0`	affected	—
`8.12.1`	affected	—
`8.12.0`	affected	—
`8.11.1`	affected	—
`8.11.0`	affected	—
`8.10.1`	affected	—
`8.10.0`	affected	—
`8.9.1`	affected	—
`8.9.0`	affected	—
`8.8.0`	affected	—
`8.7.1`	affected	—
`8.7.0`	affected	—
`8.6.0`	affected	—
`8.5.0`	affected	—
`8.4.0`	affected	—
`8.3.0`	affected	—
`8.2.1`	affected	—
`8.2.0`	affected	—
`8.1.2`	affected	—
`8.1.1`	affected	—
`8.1.0`	affected	—
`8.0.1`	affected	—
`8.0.0`	affected	—
`7.88.1`	affected	—
`7.88.0`	affected	—
`7.87.0`	affected	—
`7.86.0`	affected	—
`7.85.0`	affected	—
`7.84.0`	affected	—
`7.83.1`	affected	—
`7.83.0`	affected	—
`7.82.0`	affected	—
`7.81.0`	affected	—
`7.80.0`	affected	—
`7.79.1`	affected	—
`7.79.0`	affected	—
`7.78.0`	affected	—
`7.77.0`	affected	—
`7.76.1`	affected	—
`7.76.0`	affected	—
`7.75.0`	affected	—
`7.74.0`	affected	—
`7.73.0`	affected	—
`7.72.0`	affected	—
`7.71.1`	affected	—
`7.71.0`	affected	—
`7.70.0`	affected	—
`7.69.1`	affected	—
`7.69.0`	affected	—
`7.68.0`	affected	—
`7.67.0`	affected	—
`7.66.0`	affected	—
`7.65.3`	affected	—
`7.65.2`	affected	—
`7.65.1`	affected	—
`7.65.0`	affected	—
`7.64.1`	affected	—
`7.64.0`	affected	—
`7.63.0`	affected	—
`7.62.0`	affected	—
`7.61.1`	affected	—
`7.61.0`	affected	—
`7.60.0`	affected	—
`7.59.0`	affected	—
`7.58.0`	affected	—
`7.57.0`	affected	—
`7.56.1`	affected	—
`7.56.0`	affected	—
`7.55.1`	affected	—
`7.55.0`	affected	—
`7.54.1`	affected	—
`7.54.0`	affected	—
`7.53.1`	affected	—
`7.53.0`	affected	—
`7.52.1`	affected	—
`7.52.0`	affected	—
`7.51.0`	affected	—
`7.50.3`	affected	—
`7.50.2`	affected	—
`7.50.1`	affected	—
`7.50.0`	affected	—
`7.49.1`	affected	—
`7.49.0`	affected	—
`7.48.0`	affected	—
`7.47.1`	affected	—
`7.47.0`	affected	—
`7.46.0`	affected	—
`7.45.0`	affected	—
`7.44.0`	affected	—

Configuration 1 [-]

cpe:2.3:a:haxx:curl:*:*:*:*:*:*:*:*

No data.

Vendor Product Confidence Versions

Curl

100%

Version	Status	Scheme	Platform
`[7.44.0,8.21.0]`	affected	semver	—

Found an issue or want to improve our Enrichment? You can suggest it directly by opening an issue on our dedicated GitHub repository .

Remediation

No vendor fix or workaround currently provided.

Additional remediation guidance may be available on OpenCVE Cloud.

Tracking

Sign in to view the affected projects.

Advisories

No advisories yet.

No CVSS v4.0

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact None

Integrity Impact High

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

The EPSS score is 0.00897.

Exploitation poc

Automatable yes

Technical Impact partial

References

Link	Providers
https://curl.se/docs/CVE-2026-18924.html
https://curl.se/docs/CVE-2026-18924.json
https://hackerone.com/reports/3916059
https://nvd.nist.gov/vuln/detail/CVE-2026-18924
https://www.cve.org/CVERecord?id=CVE-2026-18924

History

Thu, 17 Sep 2026 12:15:00 +0000

Type	Values Removed	Values Added
Weaknesses		CWE-825
References		https://nvd.nist.gov/vuln/detail/CVE-2026-18924 https://www.cve.org/CVERecord?id=CVE-2026-18924
Metrics	threat_severity `None`	threat_severity `Low`

Fri, 11 Sep 2026 23:45:00 +0000

Type	Values Removed	Values Added
First Time appeared		Haxx Haxx curl
CPEs		cpe:2.3:a:haxx:curl::::::::
Vendors & Products		Haxx Haxx curl

Tue, 08 Sep 2026 16:30:00 +0000

Type	Values Removed	Values Added
Metrics		cvssV3_1 `{'score': 9.1, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H'}` ssvc `{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}`

Sun, 06 Sep 2026 20:15:00 +0000

Type	Values Removed	Values Added
First Time appeared		Curl Curl curl
Weaknesses		CWE-416
Vendors & Products		Curl Curl curl

Sun, 06 Sep 2026 18:00:00 +0000

Type	Values Removed	Values Added
Description		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.
Title		HTTP/2 server push UAF
References		https://curl.se/docs/CVE-2026-18924.html https://curl.se/docs/CVE-2026-18924.json https://hackerone.com/reports/3916059

Subscriptions

Curl Curl

Haxx Curl

MITRE

Status: PUBLISHED

Assigner: curl

Published: 2026-09-06T17:47:27.820Z

Updated: 2026-09-15T06:02:47.329Z

Reserved: 2026-08-05T08:31:56.125Z

Link: CVE-2026-18924

Vulnrichment

Updated: 2026-09-08T15:41:19.299Z

NVD

Status : Modified

Published: 2026-09-06T18:17:20.553

Modified: 2026-09-15T07:16:27.063

Link: CVE-2026-18924

Redhat

Severity : Low

Publid Date: 2026-09-06T17:47:27Z

Links: CVE-2026-18924 - Bugzilla

OpenCVE Enrichment

Updated: 2026-09-21T06:15:10Z

Weaknesses

Tracking

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact None

Integrity Impact High

Availability Impact High

User Interaction None

Exploitation poc

Automatable yes

Technical Impact partial

Subscriptions

JSON object

JSON object

JSON object

JSON object

JSON object