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Fencer Vulns
critical 9.8

CVE-2026-10536 json

HTTP/2 stream-dependency tree UAF

published 2026-07-03 4 mo ago modified 2026-09-15 55 d ago also EUVD-2026-41497 , GHSA-wjq8-x4qm-6mmh , JLSEC-2026-1197

cvss
9.8
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 use-after-free vulnerability exists in libcurl when an application configures an HTTP/2 stream-dependency tree via `CURLOPT_STREAM_DEPENDS` or `CURLOPT_STREAM_DEPENDS_E`, subsequently invokes `curl_easy_reset()`, and finally terminates the handle with `curl_easy_cleanup()`. During this final cleanup phase, libcurl attempts to access and modify an internal structure that was already freed during the reset operation.

Patch / fix

  • julia CURL_jll 8.21.0+0
  • julia LibCURL_jll 8.21.0+0
  • curl curl 8.14.2, 8.16.1, 8.20.1
  • curl Debian 14 8.21.0~rc2-1

debian advisories DEBIAN-CVE-2026-10536

  • curl Ubuntu 24.04 LTS 8.5.0-2ubuntu10.11
  • curl Ubuntu 25.10 8.14.1-2ubuntu1.5
  • curl Ubuntu 26.04 LTS 8.18.0-1ubuntu2.3

ubuntu advisories UBUNTU-CVE-2026-10536

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

  • curl RHEL 10.2 8.12.1-4.el10_2.7
  • libcurl RHEL 10.2 8.12.1-4.el10_2.7
  • libcurl-minimal RHEL 10.2 8.12.1-4.el10_2.7
  • curl hummingbird 1 8.21.0-0.1.1.hum1
  • libcurl hummingbird 1 8.21.0-0.1.1.hum1
  • libcurl-minimal hummingbird 1 8.21.0-0.1.1.hum1

red hat advisories RHSA-2026:80512RHSA-2026:41240

  • curl Linux Micro 6.1 8.14.1-slfo.1.1_8.1
  • curl SLES 15 SP5-LTSS, SLES 15 SP4-LTSS, SLE Micro 5.5 +8 more 8.14.1-150400.5.86.1
  • curl Linux Micro 6.0 8.14.1-7.1
  • curl SLE Module for Basesystem 15 SP7 8.14.1-150700.7.20.1
  • curl SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 8.14.1-160000.8.1
  • curl-mini SLES for SAP applications 16.0, SLES 16.0 8.14.1-160000.8.1
  • curl SLES LTSS Extended Security 12 SP5, SLES 12 SP5-LTSS 8.0.1-11.126.1
  • curl SLES for SAP 15 SP6, SLES 15 SP6-LTSS 8.14.1-150600.4.46.1

suse advisories SUSE-SU-2026:3814-1SUSE-SU-2026:22889-1SUSE-SU-2026:3043-1SUSE-SU-2026:22709-1SUSE-SU-2026:2926-1SUSE-SU-2026:2925-1

  • curl openSUSE Tumbleweed 8.21.0-1.1
  • curl openSUSE Leap 16.0 8.14.1-160000.8.1

opensuse advisories openSUSE-SU-2026:11230-1openSUSE-SU-2026:21272-1

  • curl AlmaLinux 10 8.12.1-4.el10_2.7
  • libcurl AlmaLinux 10 8.12.1-4.el10_2.7
  • libcurl-minimal AlmaLinux 10 8.12.1-4.el10_2.7

almalinux advisories ALSA-2026:80512

  • curl Rocky Linux 10 8.12.1-4.el10_2.7

rocky linux advisories RLSA-2026:80512

  • curl Alpine 3.23 8.22.0-r0
  • curl Alpine 3.24 8.21.0-r0

alpine advisories ALPINE-CVE-2026-10536

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 8.11.1-10
  • cmake Azure Linux 3.0 3.30.3-15

azure linux advisories AZL-91818AZL-91839

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-2026-10536 updated cvss 4.7

libcurl: libcurl: Use-after-free vulnerability leading to Denial of Service

  • Red Hat Enterprise Linux 10 igvm, snphost
    affected: workaround, no fix available
  • Red Hat JBoss Core Services libcurl.so
    affected: workaround, no fix planned “Will not fix”
  • Red Hat Cost Management On-Premise 1 costmanagement/costmanagement-ui-rhel10 1792605272
    fixed: vendor fix RHSA-2026:87400
  • Red Hat Enterprise Linux AppStream (v. 10) libcurl-devel 8.12.1-4.el10_2.7, curl-debuginfo 8.12.1-4.el10_2.7, curl-debugsource 8.12.1-4.el10_2.7, libcurl-debuginfo 8.12.1-4.el10_2.7, libcurl-minimal-debuginfo 8.12.1-4.el10_2.7 Red Hat Enterprise Linux BaseOS (v. 10) curl 8.12.1-4.el10_2.7, libcurl 8.12.1-4.el10_2.7, libcurl-minimal 8.12.1-4.el10_2.7
    fixed: vendor fix RHSA-2026:80512
  • Red Hat Hardened Images curl 8.21.0-0.1.1.hum1, libcurl 8.21.0-0.1.1.hum1, libcurl-minimal 8.21.0-0.1.1.hum1
    fixed: vendor fix RHSA-2026:41240
  • Red Hat JBoss Core Services 2.4.62.SP5
    fixed: vendor fix RHSA-2026:56869
  • Red Hat Confidential Compute Attestation build-of-trustee/trustee-rhel9, openshift-sandboxed-containers/osc-podvm-payload-rhel9 Red Hat Enterprise Linux 6 curl, libcurl Red Hat Enterprise Linux 7 curl, libcurl Red Hat Enterprise Linux 8 curl, libcurl, libcurl-minimal Red Hat Enterprise Linux 9 curl, rust, cargo, clippy, libcurl, rustfmt, +14 more
    not affected: vulnerable code not present
  • Red Hat Enterprise Linux 10 rust, trustee, s390utils, trustee-guest-components
    not affected: component not present
show 1 more
  • Red Hat Enterprise Linux AI (RHEL AI) 3 rust Red Hat Hardened Images rust Red Hat OpenShift Container Platform 4 openshift/ose-rhel-coreos-8, openshift/ose-rhel-coreos-9 Red Hat OpenShift Container Platform 5 openshift/ose-rhel-coreos-9 Red Hat OpenShift Dev Spaces devspaces/code-rhel9 Red Hat Trusted Profile Analyzer rhtpa/rhtpa-trustification-service-rhel9
    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
total
Assessed
4 mo ago

Exploit prediction

0.60% 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/3751697 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CISA ADP 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CNA 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
OSV 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected packages

ecosystem package affected fixed in
julia CURL_jll
>=8.5.0+0, <8.21.0+0
8.21.0+0
julia LibCURL_jll
>=7.88.1+0, <8.21.0+0
8.21.0+0

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.

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