NVD / CVE Program· CNA curl

CVE-2026-10536: HTTP/2 stream-dependency tree UAF

CriticalCVSS 9.8 · v3.1—No exploit Fix available

Noroxi assessment

Priority: Monitor (action score 39/100)

The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
Probability of exploitation in the next 30 days: 0.59% (FIRST EPSS).
Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
According to CISA the attack is automatable: targets can be found by mass scanning.
Fixed version: curl curl 8.14.2, 8.16.1, 8.20.1; azl3 curl 8.11.1-9 on Azure Linux 3.0 8.11.1-10.

Low priority for now. Upgrade to curl curl 8.14.2, 8.16.1, 8.20.1; azl3 curl 8.11.1-9 on Azure Linux 3.0 8.11.1-10 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

Published: Jul 3, 2026
Updated: Sep 15, 2026
EPSS: 0.5% · 49th percentile
CWE: CWE-416

Report tools

JSON

Action score

Monitor

Low priority for now.

CVSS: 39 / 40 · 9.8 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 0.5%

CISA SSVC decision

Exploitation: proof of concept
Automatable: yes
Technical impact: total

Vulnrichment: CISA's decision-tree inputs.

Get told when this record changes

Not in KEV: no record of exploitation in the wild
No public exploit code on record
A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Is your version affected? Check it

Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

Vendor	Product	CPE
haxx	curl	cpe:2.3:a:haxx:curl

Versions reported by the vendor

Affected version ranges reported by the assigning authority (curl). Independent of NVD's CPE analysis and usually ahead of it.

curl curl
- 8.20.0, 8.19.0, 8.18.0, 8.17.0, 8.16.0, 8.15.0, 8.14.1, 8.14.0, 8.13.0, 8.12.1, 8.12.0, 8.11.1 … (+21)affected
- 7.88.0 and later · before 8.14.2affected · semver
- 8.15.0 and later · before 8.16.1affected · semver
- 8.17.0 and later · before 8.20.1affected · semver
- 71b7e0161032927cdfb4e75ea40f65b8898b3956 and later · before bfbff7852f050232edd3e5ca5c6bf2021c340f5aaffected · git

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

haxx curl7.88.0 and later · before 8.21.0

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

Ecosystem	Package	Affected range	Fix
AlmaLinux:10	curl	before 8.12.1-4.el10_2.7	8.12.1-4.el10_2.7
AlmaLinux:10	libcurl	before 8.12.1-4.el10_2.7	8.12.1-4.el10_2.7
AlmaLinux:10	libcurl-devel	before 8.12.1-4.el10_2.7	8.12.1-4.el10_2.7
AlmaLinux:10	libcurl-minimal	before 8.12.1-4.el10_2.7	8.12.1-4.el10_2.7
Alpine:v3.23	curl	from 7.88.0 · before 8.22.0-r0	8.22.0-r0
Alpine:v3.24	curl	from 7.88.0 · before 8.21.0-r0	8.21.0-r0
Debian:12	curl	from 0	—
Debian:14	curl	before 8.21.0~rc2-1	8.21.0~rc2-1
openSUSE:Leap 16.0	curl	before 8.14.1-160000.8.1	8.14.1-160000.8.1
openSUSE:Tumbleweed	curl	before 8.21.0-1.1	8.21.0-1.1
Red Hat:enterprise_linux:10.2	curl	before 0:8.12.1-4.el10_2.7	0:8.12.1-4.el10_2.7
Red Hat:enterprise_linux:10.2	curl-debuginfo	before 0:8.12.1-4.el10_2.7	0:8.12.1-4.el10_2.7
Red Hat:enterprise_linux:10.2	curl-debugsource	before 0:8.12.1-4.el10_2.7	0:8.12.1-4.el10_2.7
Red Hat:enterprise_linux:10.2	libcurl	before 0:8.12.1-4.el10_2.7	0:8.12.1-4.el10_2.7
Red Hat:enterprise_linux:10.2	libcurl-debuginfo	before 0:8.12.1-4.el10_2.7	0:8.12.1-4.el10_2.7
Red Hat:enterprise_linux:10.2	libcurl-devel	before 0:8.12.1-4.el10_2.7	0:8.12.1-4.el10_2.7
Red Hat:enterprise_linux:10.2	libcurl-minimal	before 0:8.12.1-4.el10_2.7	0:8.12.1-4.el10_2.7
Red Hat:enterprise_linux:10.2	libcurl-minimal-debuginfo	before 0:8.12.1-4.el10_2.7	0:8.12.1-4.el10_2.7
Red Hat:hummingbird:1	curl	before 0:8.21.0-0.1.1.hum1	0:8.21.0-0.1.1.hum1
Red Hat:hummingbird:1	libcurl	before 0:8.21.0-0.1.1.hum1	0:8.21.0-0.1.1.hum1
Red Hat:hummingbird:1	libcurl-devel	before 0:8.21.0-0.1.1.hum1	0:8.21.0-0.1.1.hum1
Red Hat:hummingbird:1	libcurl-minimal	before 0:8.21.0-0.1.1.hum1	0:8.21.0-0.1.1.hum1
Rocky Linux:10	curl	before 0:8.12.1-4.el10_2.7	0:8.12.1-4.el10_2.7
SUSE:Linux Enterprise Installer Updates 15 SP4	curl	before 8.14.1-150400.5.86.1	8.14.1-150400.5.86.1

Same product

haxx: all records

Other highest-scoring records for the same primary product.

CVE-2021-22901curl 7.75.0 through 7.76.1 suffers from a use-after-free vulnerability resulting in already freed memory being used when a TLS 1.3 session…
51Plan
CVE-2023-38039When curl retrieves an HTTP response, it stores the incoming headers so that they can be accessed later via the libcurl headers API.
47Plan
CVE-2024-2398HTTP/2 push headers memory-leak
45Plan

Published before and after this one in the same product

← EarlierCVE-2026-7009May 13, 2026 · OCSP stapling bypass with Apple SecTrust
21Monitor
← EarlierCVE-2026-7168May 13, 2026 · cross-proxy Digest auth state leak
21Monitor
Later →CVE-2026-11352Jul 3, 2026 · QUIC zero-length UDP datagrams busy-loop
30Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / package	Fixed version	Source
curl curl	8.14.2	Vendor (CNA)
curl curl	8.16.1	Vendor (CNA)
curl curl	8.20.1	Vendor (CNA)
curl curl	bfbff7852f050232edd3e5ca5c6bf2021c340f5a	Vendor (CNA)
azl3 curl 8.11.1-9 on Azure Linux 3.0	8.11.1-10 · CBL-Mariner Releases	Microsoft (MSRC)
almalinux:curl	8.12.1-4.el10_2.7 · AlmaLinux:10	Package registry (OSV)
almalinux:libcurl	8.12.1-4.el10_2.7 · AlmaLinux:10	Package registry (OSV)
almalinux:libcurl-devel	8.12.1-4.el10_2.7 · AlmaLinux:10	Package registry (OSV)
almalinux:libcurl-minimal	8.12.1-4.el10_2.7 · AlmaLinux:10	Package registry (OSV)
alpine:curl	8.22.0-r0 · Alpine:v3.23	Package registry (OSV)
debian:curl	8.21.0~rc2-1 · Debian:14	Package registry (OSV)
opensuse:curl	8.21.0-1.1 · openSUSE:Tumbleweed	Package registry (OSV)
red hat:curl	0:8.21.0-0.1.1.hum1 · Red Hat:hummingbird:1	Package registry (OSV)
red hat:curl-debuginfo	0:8.12.1-4.el10_2.7 · Red Hat:enterprise_linux:10.2	Package registry (OSV)
red hat:curl-debugsource	0:8.12.1-4.el10_2.7 · Red Hat:enterprise_linux:10.2	Package registry (OSV)
red hat:libcurl	0:8.21.0-0.1.1.hum1 · Red Hat:hummingbird:1	Package registry (OSV)
red hat:libcurl-debuginfo	0:8.12.1-4.el10_2.7 · Red Hat:enterprise_linux:10.2	Package registry (OSV)
red hat:libcurl-devel	0:8.21.0-0.1.1.hum1 · Red Hat:hummingbird:1	Package registry (OSV)
red hat:libcurl-minimal	0:8.21.0-0.1.1.hum1 · Red Hat:hummingbird:1	Package registry (OSV)
red hat:libcurl-minimal-debuginfo	0:8.12.1-4.el10_2.7 · Red Hat:enterprise_linux:10.2	Package registry (OSV)
rocky linux:curl	0:8.12.1-4.el10_2.7 · Rocky Linux:10	Package registry (OSV)
suse:curl	8.14.1-160000.8.1 · SUSE:Linux Micro 6.2	Package registry (OSV)
suse:curl-mini	8.14.1-160000.8.1 · SUSE:Linux Enterprise Server 16.0	Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

Stefan Eissingremediation developer
Joshua Rogers (Aisle Research)finder

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

CVE-2026-1892465 days apartHTTP/2 server push UAF
36Monitor
CVE-2026-8022965 days apartOpenSSL provider use-after-free
30Monitor
CVE-2026-3805114 days apartuse after free in SMB connection reuse
30Monitor
CVE-2026-90800 days apartUAF after pause in socket callback
29Monitor

Not on record for this CVE: EPSS history · patch commit or PR link · public bounty program.

Technical details

Attack conditions

Anyone who can reach it over the internet can trigger it.
No account or password is required.
No user action is required.
No special conditions are required; it is repeatable.

If successful

Confidentiality: high · data can be read
Integrity: high · data or configuration can be modified
Availability: high · the service can be disrupted

Attack vector: Network
Attack complexity: Low
Privileges required: None
User interaction: None
Scope: Unchanged
Confidentiality impact: High
Integrity impact: High
Availability impact: High

Weakness class (CWE)

CWE-416 · Use After Free

CVSS vector

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

nvd-secondary

Root cause

After a memory region is freed, another reference pointing to it is still used. By then, the same region may have been allocated for different data.

The bug in code

The whole CWE-416 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

1free(dev->buf);
2/* ... another thread is still running ... */
3process(dev->buf);

Fixed

1lock(&dev->lock);
2free(dev->buf);
3dev->buf = NULL;
4unlock(&dev->lock);

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log (1)

Fix✗ → ✓Sep 28, 2026, 10:09 PM UTC

For records you follow, these changes also arrive as notifications. →

References

curl.se/docs/CVE-2026-10536.html

Show all references (1 more)

curl.se/docs/CVE-2026-10536.json

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records