Public proof of conceptFix available

CVE-2026-10536

Q: Is CVE-2026-10536 actively exploited?

A proof-of-concept exploit exists for CVE-2026-10536, but active exploitation has not been confirmed at this time.

Q: What is the CVSS score for CVE-2026-10536?

CVE-2026-10536 has a CVSS v3 base score of 9.8 (CRITICAL severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

A public proof of concept exists; no exploitation attested.

Published2026-07-03
Fixed in8.21.0
WeaknessCWE-416

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

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.

Timeline

dates in UTC

2026-07-0307:16CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 21:37 UTC

Indicators tagged with this CVE, per day0 indicators over 7 days

Block these indicators

Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2026-10536?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2026-10536?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD

Haxx curl

Branch	Affected	Fixed in	Source
8.21	≥ 7.88.0, < 8.21.0	8.21.0	NVD

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

libcurlAlmaLinux:10all versions · fixed in 8.12.1-4.el10_2.7and 3 other packages

Vendor advisories

CVE-2026-10536 Red Hat Product Security60 products fixed · 3 known affected
libcurl: libcurl: Use-after-free vulnerability leading to Denial of Service
igvm.src as a component of Red Hat Enterprise Linux 10 · snphost.src as a component of Red Hat Enterprise Linux 10 · libcurl.so as a component of Red Hat JBoss Core Services
RHSA-2026:87400 Red Hat Product Security1 product fixed
Red Hat Security Advisory: Red Hat Cost Management On-Premise container image update
RHSA-2026:80512 Red Hat Product Security49 products fixed
Red Hat Security Advisory: curl security update
RHSA-2026:56869 Red Hat Product Security1 product fixed
Red Hat Security Advisory: Red Hat JBoss Core Services Apache HTTP Server 2.4.62 SP5 security update
RHSA-2026:41240 Red Hat Product Security9 products fixed
Red Hat Security Advisory: Red Hat Hardened Images RPMs Security Update

Full record on NVD

Fix

Update Haxx curl to 8.21.0
Vendor fix Red Hat Product Security RHSA-2026:87400 · 1 productThe container image provided by this update can be downloaded from the Red Hat container registry at registry.redhat.io using the "podman pull" command.
Vendor fix Red Hat Product Security RHSA-2026:80512 · 49 productsFor details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
Vendor fix Red Hat Product Security RHSA-2026:56869 · 1 productBefore applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
Vendor fix Red Hat Product Security RHSA-2026:41240 · 9 productsFor details on how to apply this update, which includes the changes described in this advisory, refer to: https://images.redhat.com/
Workaround from the vendor Red Hat Product Security RHSA-2026:87400 · 1 productTo mitigate this issue, avoid configuring HTTP/2 stream dependencies within applications utilizing libcurl. This functionality is considered deprecated and its use is required to trigger the vulnerability.
No fix available, says the vendor Red Hat Product Security CVE-2026-10536 · 2 productsAffected

Advisories and patches

curl.sePatch · Vendor Advisory
curl.seVendor Advisory

Detection

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: none listed

Sources

CISA-ADPSSVC decisionpoc2026-07-06
OpenCVESSVC decisionpoc—
CISA-ADPCVSS 3.19.82026-07-06
CNAweakness (CWE)CWE-416read 2026-10-23
NVDweakness (CWE)CWE-416read 2026-10-23
FIRST EPSSEPSS score0.6 %2026-10-23
OSVaffected packages—

Technical details

CVSS v3 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Published: 2026-07-03
Last Modified: 2026-09-15
NVD status: Modified

Frequently asked questions

What is CVE-2026-10536?

Is CVE-2026-10536 actively exploited?

A proof-of-concept exploit exists for CVE-2026-10536, but active exploitation has not been confirmed at this time.

What is the CVSS score for CVE-2026-10536?

CVE-2026-10536 has a CVSS v3 base score of 9.8 (CRITICAL severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

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