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CVE-2026-9547· NVD / CVE Program· CNA curl

SSH improper host validation

Noroxi assessment

Priority: Monitor (action score 29/100)

  • 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: 0.32% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. Special conditions such as timing or configuration are required.
  • Fixed version: curl curl 0b8dbbc63c98777e4584cb9fbd71df3464008ad1, 8.14.2, 8.16.1.

Low priority for now. Upgrade to curl curl 0b8dbbc63c98777e4584cb9fbd71df3464008ad1, 8.14.2, 8.16.1 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

When a libcurl-based application performs transfers via `SCP://` or `SFTP://` and utilizes the `CURLOPT_SSH_KEYFUNCTION` callback, it may silently accept an untrusted server. This vulnerability occurs when a server presents a host key type that does not match the specific key type already recorded for that host in the `known_hosts` file. Instead of rejecting the mismatch, the callback mechanism fails to properly enforce the restriction, allowing the connection to succeed without warning and risking a potential man-in-the-middle attack.

HighCVSS 7.4 · v3.1—No exploit Fix available
Published
Jul 3, 2026
Updated
Sep 15, 2026
EPSS
0.3% · 24th percentile

Report tools

JSON

Action score

29

Monitor

Low priority for now.

CVSS
29 / 40 · 7.4 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.3%

CISA SSVC decision

Exploitation
proof of concept
Automatable
no
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.

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When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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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.

VendorProduct
haxxcurl

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This vulnerability is about certificate validation or weak cryptography. The free SSL checker tests your certificate, enabled TLS versions and weak ciphers.

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Affected versions

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

  • haxx curl7.69.0 and later · before 8.21.0

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 … (+24)affected
    • 7.69.0 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
    • 507cf6a13db0375eadd4655b4c64710db29e9cf2 and later · before 0b8dbbc63c98777e4584cb9fbd71df3464008ad1affected · git

Package-level exposure

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

EcosystemPackageAffected rangeFix
AlmaLinux:9curlbefore 7.76.1-40.el9_8.57.76.1-40.el9_8.5
AlmaLinux:9curl-minimalbefore 7.76.1-40.el9_8.57.76.1-40.el9_8.5
AlmaLinux:9libcurlbefore 7.76.1-40.el9_8.57.76.1-40.el9_8.5
AlmaLinux:9libcurl-develbefore 7.76.1-40.el9_8.57.76.1-40.el9_8.5
AlmaLinux:9libcurl-minimalbefore 7.76.1-40.el9_8.57.76.1-40.el9_8.5
Alpine:v3.23curlfrom 7.69.0 · before 8.22.0-r08.22.0-r0
Alpine:v3.24curlfrom 7.69.0 · before 8.21.0-r08.21.0-r0
Debian:12curlfrom 0—
Debian:14curlbefore 8.21.0~rc2-18.21.0~rc2-1
openSUSE:Leap 16.0curlbefore 8.14.1-160000.8.18.14.1-160000.8.1
openSUSE:Tumbleweedcurlbefore 8.21.0-1.18.21.0-1.1
Red Hat:enterprise_linux_eus:10.0curlbefore 0:8.12.1-1.el10_0.100:8.12.1-1.el10_0.10
Red Hat:enterprise_linux_eus:10.0curl-debuginfobefore 0:8.12.1-1.el10_0.100:8.12.1-1.el10_0.10
Red Hat:enterprise_linux_eus:10.0curl-debugsourcebefore 0:8.12.1-1.el10_0.100:8.12.1-1.el10_0.10
Red Hat:enterprise_linux_eus:10.0libcurlbefore 0:8.12.1-1.el10_0.100:8.12.1-1.el10_0.10
Red Hat:enterprise_linux_eus:10.0libcurl-debuginfobefore 0:8.12.1-1.el10_0.100:8.12.1-1.el10_0.10
Red Hat:enterprise_linux_eus:10.0libcurl-develbefore 0:8.12.1-1.el10_0.100:8.12.1-1.el10_0.10
Red Hat:enterprise_linux_eus:10.0libcurl-minimalbefore 0:8.12.1-1.el10_0.100:8.12.1-1.el10_0.10
Red Hat:enterprise_linux_eus:10.0libcurl-minimal-debuginfobefore 0:8.12.1-1.el10_0.100:8.12.1-1.el10_0.10
Red Hat:enterprise_linux:10.2curlbefore 0:8.12.1-4.el10_2.30:8.12.1-4.el10_2.3
Red Hat:enterprise_linux:10.2curl-debuginfobefore 0:8.12.1-4.el10_2.30:8.12.1-4.el10_2.3
Red Hat:enterprise_linux:10.2curl-debugsourcebefore 0:8.12.1-4.el10_2.30:8.12.1-4.el10_2.3
Red Hat:enterprise_linux:10.2libcurlbefore 0:8.12.1-4.el10_2.30:8.12.1-4.el10_2.3
Red Hat:enterprise_linux:10.2libcurl-debuginfobefore 0:8.12.1-4.el10_2.30:8.12.1-4.el10_2.3

+26

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 t
    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-2026-9545Jul 3, 2026 · exposing HTTP/3 early data
    30Monitor
  • ← EarlierCVE-2026-9546Jul 3, 2026 · A vulnerability in libcurl caused the HTTP `Referer:` header to persist even when explicitly cleared.
    30Monitor
  • Later →CVE-2026-13608Sep 6, 2026 · OpenLDAP SASL authentication bypass
    29Monitor

Remediation

Which version to upgrade to

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

Product / packageFixed versionSource
curl curl0b8dbbc63c98777e4584cb9fbd71df3464008ad1Vendor (CNA)
curl curl8.14.2Vendor (CNA)
curl curl8.16.1Vendor (CNA)
curl curl8.20.1Vendor (CNA)
almalinux:curl7.76.1-40.el9_8.5 · AlmaLinux:9Package registry (OSV)
almalinux:curl-minimal7.76.1-40.el9_8.5 · AlmaLinux:9Package registry (OSV)
almalinux:libcurl7.76.1-40.el9_8.5 · AlmaLinux:9Package registry (OSV)
almalinux:libcurl-devel7.76.1-40.el9_8.5 · AlmaLinux:9Package registry (OSV)
almalinux:libcurl-minimal7.76.1-40.el9_8.5 · AlmaLinux:9Package registry (OSV)
alpine:curl8.22.0-r0 · Alpine:v3.23Package registry (OSV)
debian:curl8.21.0~rc2-1 · Debian:14Package registry (OSV)
opensuse:curl8.21.0-1.1 · openSUSE:TumbleweedPackage registry (OSV)
red hat:curl0:8.21.0-0.1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:curl-debuginfo0:7.76.1-40.el9_8.5 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
red hat:curl-debugsource0:7.76.1-40.el9_8.5 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
red hat:curl-minimal0:7.76.1-40.el9_8.5 · Red Hat:enterprise_linux:9::baseosPackage registry (OSV)
red hat:curl-minimal-debuginfo0:7.76.1-40.el9_8.5 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
red hat:libcurl0:7.76.1-40.el9_8.5 · Red Hat:enterprise_linux:9::baseosPackage registry (OSV)
red hat:libcurl0:8.21.0-0.1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:libcurl-debuginfo0:7.76.1-40.el9_8.5 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
red hat:libcurl-devel0:7.76.1-40.el9_8.5 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
red hat:libcurl-devel0:8.21.0-0.1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:libcurl-minimal0:7.76.1-40.el9_8.5 · Red Hat:enterprise_linux:9::baseosPackage registry (OSV)
red hat:libcurl-minimal0:8.21.0-0.1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:libcurl-minimal-debuginfo0:7.76.1-40.el9_8.5 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
rocky linux:curl0:7.76.1-40.el9_8.5 · Rocky Linux:9Package registry (OSV)
suse:curl8.14.1-160000.8.1 · SUSE:Linux Micro 6.2Package registry (OSV)
suse:curl-mini8.14.1-160000.8.1 · SUSE:Linux Enterprise Server 16.0Package 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.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

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

Variant candidates

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

  • CVE-2026-120640 days apartproto-default skips SSH verification
    30Monitor
  • CVE-2025-15079176 days apartlibssh global known_hosts override
    21Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

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.
  • Special conditions such as timing or configuration are required.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
none
Attack vector
Network
Attack complexity
High
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
None

Weakness class (CWE)

CWE-297 · Improper Validation of Certificate with Host Mismatch

CVSS vector

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

nvd-secondary

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✗ → ✓

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

References

Show all references (1 more)

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

All records