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Fencer Intel
critical 9.1

CVE-2026-18924 json

HTTP/2 server push UAF

published 2026-09-06 2 mo ago modified 2026-09-15 55 d ago also EUVD-2026-72165

cvss
9.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.6%
EPSS 0.6% chance of exploitation in 30 days, percentile 48%
public exploits
0
none known

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.

Patch / fix

  • curl curl 8.14.2, 8.16.1, 8.20.1, 8.22.0
  • curl Debian 14 8.22.0~rc2-1

debian advisories DEBIAN-CVE-2026-18924

  • curl Ubuntu 22.04 LTS 7.81.0-1ubuntu1.29
  • curl Ubuntu 24.04 LTS 8.5.0-2ubuntu10.15
  • curl Ubuntu 26.10 8.20.0-2ubuntu11
  • curl Ubuntu 26.04 LTS 8.18.0-1ubuntu2.7
  • curl Ubuntu Pro 16.04 LTS 7.47.0-1ubuntu2.19+esm20
  • curl Ubuntu Pro 18.04 LTS 7.58.0-2ubuntu3.24+esm14
  • curl Ubuntu Pro 20.04 LTS 7.68.0-1ubuntu2.25+esm9

ubuntu advisories UBUNTU-CVE-2026-18924

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • rust hummingbird 1 1.98.0-1.hum1
  • cargo hummingbird 1 1.98.0-1.hum1
  • clippy hummingbird 1 1.98.0-1.hum1
  • rustfmt hummingbird 1 1.98.0-1.hum1
  • rust-gdb hummingbird 1 1.98.0-1.hum1
  • rust-src hummingbird 1 1.98.0-1.hum1
  • rust-lldb hummingbird 1 1.98.0-1.hum1
  • rust-analyzer hummingbird 1 1.98.0-1.hum1

red hat advisories RHSA-2026:63514RHSA-2026:63161

  • curl SLE Module for Basesystem 15 SP7 8.22.0-150700.7.33.1
  • curl SLES 15 SP5-LTSS, SLES 15 SP4-LTSS, SLE Micro 5.5 +8 more 8.14.1-150400.5.98.1
  • curl SLES for SAP 15 SP6, SLES 15 SP6-LTSS 8.22.0-150600.4.58.1

suse advisories SUSE-SU-2026:5069-1SUSE-SU-2026:5068-1SUSE-SU-2026:4954-1

  • curl openSUSE Tumbleweed 8.22.0-1.1

opensuse advisories openSUSE-SU-2026:11696-1

  • curl Alpine 3.24, Alpine 3.23 8.22.0-r0

alpine advisories ALPINE-CVE-2026-18924

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • curl Azure Linux 3.0 8.11.1-12

azure linux advisories AZL-99764

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-18924 updated cvss 3.7

curl: libcurl: Use-after-free in HTTP/2 Server Push with shared connections

  • Red Hat Confidential Compute Attestation build-of-trustee/trustee-rhel9, openshift-sandboxed-containers/osc-podvm-payload-rhel9 Red Hat Enterprise Linux 8 curl, libcurl, libcurl-minimal Red Hat Enterprise Linux 9 curl, rust, cargo, clippy, libcurl, rustfmt, +13 more Red Hat Enterprise Linux 10 curl, igvm, rust, snphost, trustee, s390utils Red Hat Enterprise Linux AI (RHEL AI) 3 rust Red Hat OpenShift Container Platform 4 openshift/ose-rhel-coreos-8, openshift/ose-rhel-coreos-9
    +3 more products
    Red Hat OpenShift Container Platform 5 openshift/ose-rhel-coreos-9 Red Hat OpenShift Dev Spaces devspaces/code-rhel9 Red Hat Satellite 6 puppet-agent, openvox-agent
    affected: workaround, no fix available “Fix deferred”
  • Red Hat OpenShift AI (RHOAI) rhoai/odh-core-bff-rhel9, rhoai/odh-dashboard-rhel9, rhoai/odh-mod-arch-maas-rhel9, rhoai/odh-mod-arch-automl-rhel9, rhoai/odh-mod-arch-gen-ai-rhel9, rhoai/odh-mod-arch-mlflow-rhel9, +6 more
    under investigation
  • Red Hat Hardened Images rust 1.98.0-1.hum1, cargo 1.98.0-1.hum1, clippy 1.98.0-1.hum1, curl 8.22.0-0.1.hum1, rustfmt 1.98.0-1.hum1, rust-gdb 1.98.0-1.hum1, +14 more
    fixed: vendor fix RHSA-2026:63514
  • Red Hat Enterprise Linux 6 curl, libcurl Red Hat Enterprise Linux 7 curl, libcurl
    not affected: vulnerable code not present
  • Red Hat Hardened Images openshell
    not affected: component not present
  • Red Hat OpenShift AI (RHOAI) rhoai/odh-mlflow-rhel9, rhoai/odh-kube-rbac-proxy-rhel9, rhoai/odh-maas-controller-rhel9, rhoai/odh-mlflow-operator-rhel9, rhoai/odh-model-controller-rhel9, rhoai/odh-ogx-k8s-operator-rhel9, +14 more Red Hat Satellite 6 foreman, foreman-cli, foreman-ec2, foreman-gce, foreman-ovirt, foreman-vmware, +9 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
yes
Technical impact
partial
Assessed
2 mo ago

Exploit prediction

0.58% chance of exploitation in the next 30 days, higher than 48% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • hackerone.com https://hackerone.com/reports/3916059 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CISA ADP 3.1 9.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H
CNA 3.1 9.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H

Affected products

  • curl curl

Classification

Weakness

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.