CVE-2026-9547
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Description
A flaw was found in curl. When a libcurl-based application uses SCP:// or SFTP:// for transfers and employs the CURLOPT_SSH_KEYFUNCTION callback, it may silently accept an untrusted server. This occurs if the server's host key type differs from the one stored in the known_hosts file. The callback mechanism fails to enforce the host key restriction, enabling a connection to an untrusted server and risking a man-in-the-middle attack.
Statement
This is an Important flaw where libcurl-based applications performing SCP or SFTP transfers with the CURLOPT_SSH_KEYFUNCTION callback may silently accept an untrusted server. This occurs when a server presents a host key type that differs from the one recorded in the known_hosts file, bypassing a critical host key verification and enabling potential man-in-the-middle attacks. The vulnerability requires specific application callback usage, not a general curl client default.
Mitigation
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
Additional information
- This content is not included.Bugzilla 2496758: curl: curl: Man-in-the-middle attack via SSH host key bypass
- Content from cwe.mitre.org is not included.CWE-347: Improper Verification of Cryptographic Signature
External References
Content from www.cve.org is not included.https://www.cve.org/CVERecord?id=CVE-2026-9547
Content from nvd.nist.gov is not included.https://nvd.nist.gov/vuln/detail/CVE-2026-9547
Content from curl.se is not included.https://curl.se/docs/CVE-2026-9547.html
Content from curl.se is not included.https://curl.se/docs/CVE-2026-9547.json
Content from hackerone.com is not included.https://hackerone.com/reports/3751712
Affected Packages and Issued Red Hat Security Errata
Unless explicitly stated as not affected, all previous versions of packages in any minor update stream of a product listed here should be assumed vulnerable, although may not have been subject to full analysis.
| Products / Services | Components | State | Errata |
|---|---|---|---|
| Red Hat Enterprise Linux 10 | curl | Affected | |
| Red Hat Enterprise Linux 6 | curl | Affected | |
| Red Hat Enterprise Linux 7 | curl | Affected | |
| Red Hat Enterprise Linux 8 | curl | Affected | |
| Red Hat Enterprise Linux 9 | curl | Affected | |
| Red Hat Hardened Images | curl-main | Fixed | RHSA-2026:29017 |
| Red Hat Hardened Images | rust-main | Fixed | RHSA-2026:34975 |
| Red Hat OpenShift Container Platform 4 | rhcos | Affected | |
| Red Hat OpenShift Dev Spaces | devspaces/code-rhel9 | Affected | |
| Red Hat Trusted Profile Analyzer | rhtpa/rhtpa-trustification-service-rhel9 | Affected |
Common Vulnerability Scoring System (CVSS) Score Details
Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authorities (CNA) source for its products and services (see Red Hat classifications ).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| CVSS v3 Base Score | 7.4 | N/A | 7.4 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | High | N/A | High |
| Privileges Required | None | N/A | None |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality Impact | High | N/A | High |
| Integrity Impact | High | N/A | High |
| Availability Impact | None | N/A | None |
CVSS v3 Vector
Red Hat CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
cve.org CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
Frequently Asked Questions
Why is Red Hat's CVSS v3 score or Impact different from other vendors?
For more information, see https://access.redhat.com/solutions/762393.
My product is listed as "Under investigation" or "Affected", when will Red Hat release a fix for this vulnerability?
- "Under investigation" doesn't necessarily mean that the product is affected by this vulnerability. It only means that our Analysis Team is still working on determining whether the product is affected and how it is affected.
- "Affected" means that our Analysis Team has determined that this product is affected by this vulnerability and might release a fix to address this in the near future.
What can I do if my product is listed as "Will not fix"?
Available options depend mostly on the Impact of the vulnerability and the current Life Cycle phase of your product. Overall, you have the following options:
- Upgrade to a supported product version that includes a fix for this vulnerability (recommended).
- Apply a mitigation (if one exists).
- Open a This content is not included.support case to request a prioritization of releasing a fix for this vulnerability.
What can I do if my product is listed as "Fix deferred"?
Available options depend mostly on the Impact of the vulnerability and the current Life Cycle phase of your product. Overall, you have the following options:
- Apply a mitigation (if one exists).
- Open a This content is not included.support case to request a prioritization of releasing a fix for this vulnerability.
- Red Hat Engineering focuses on addressing high-priority issues based on their complexity or limited lifecycle support. Therefore, lower-priority issues will not receive immediate fixes.
What is a mitigation?
I have a Red Hat product but it is not in the above list, is it affected?
Why is my security scanner reporting my product as vulnerable to this vulnerability even though my product version is fixed or not affected?
My product is listed as "Out of Support Scope". What does this mean?
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