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Fencer Vulns
critical 9.1

CVE-2026-18924 json

HTTP/2 server push UAF

published 2026-09-06 2 mo ago modified 2026-09-15 54 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, 2026-11-08).

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 Vulns 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.