CVSS 9.1 · CRITICAL

CVE-2026-18924Use-after-free vulnerability in libcurl

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.

View on NVD

Analysis

A critical use-after-free vulnerability has been identified in libcurl's HTTP/2 Server Push implementation. This flaw can lead to memory corruption or crashes in applications that share connections across handles while using HTTP/2.

Relevant roles

BackendciberseguridadLinuxDockerPythonPhp

Severity

Score: 9.1(CRITICAL)

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

AV: NETWORK

AC: LOW

PR: NONE

UI: NONE

S: UNCHANGED

C: NONE

I: HIGH

A: HIGH

Weakness (CWE): CWE-416

EPSS

Probability of exploitation (next 30 days): 0.0021 (0.2%)

Percentile: 10.7%

EPSS: 2026-09-08

Technical 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: 9/6/2026, 6:17:20 PM

Last modified: 9/8/2026, 4:18:06 PM

References

How to read this card

Actively exploited

KEV (Known Exploited Vulnerabilities) is CISA's catalog of CVEs confirmed as actively exploited in the real world. If a CVE is on KEV, someone is already using it in attacks.

CVSS 10.0

CVSS 10.0 — the theoretical maximum severity. Remotely exploitable, no privileges required, total impact. Not yet confirmed as exploited in the wild, but patch now. Widely used software only: a 10.0 in a niche plugin does not make it here.

AI-recommended

A language model reviewed the CVE and judged that it affects widely deployed software or common developer tooling. A human on the team approved publication before it landed here.

Impact categories the AI evaluates

widely_deployed_infra — Linux kernel, OpenSSL, glibc, k8s, Docker, nginx, OpenSSH.

popular_dev_tooling — Node.js, Python, Go, React, Next.js, common npm/pip libraries.

common_consumer_software — Chrome, Firefox, Windows, macOS, popular mobile apps.

enterprise_saas — GitHub, GitLab, Atlassian, Salesforce, Cisco, Fortinet, Ivanti.

niche_software — Regional CMSs, hobby tools, rarely used libraries.

not_relevant — Vendor-specific firmware, discontinued software.

EPSS — EPSS (Exploit Prediction Scoring System) by FIRST.org estimates the probability that a CVE will be exploited in the next 30 days. Range is 0 to 1; very fresh CVEs typically score low until evidence accumulates.