Host impersonation via global known_hosts fallback
Published Jan 8, 2026 · Updated Jan 8, 2026
Improper SSH host verification in curl 7.58.0 through 8.17.0 allows man-in-the-middle attackers to impersonate SCP or SFTP hosts. With the libssh backend, libcurl sets a custom known_hosts file but leaves libssh's build-time global file enabled, so a host absent from the custom file is accepted when it appears globally. Exploitation requires a configured known_hosts file, a libssh-based build, user interaction to start the transfer, and a network position able to intercept it; the result is unauthorized trust in the attacker's SSH host.
Summary
What happened
Improper SSH host verification in curl 7.58.0 through 8.17.0 allows man-in-the-middle attackers to impersonate SCP or SFTP hosts. With the libssh backend, libcurl sets a custom known_hosts file but leaves libssh's build-time global file enabled, so a host absent from the custom file is accepted when it appears globally. Exploitation requires a configured known_hosts file, a libssh-based build, user interaction to start the transfer, and a network position able to intercept it; the result is unauthorized trust in the attacker's SSH host.
The record
- CVE
- CVE-2025-15079
- Published
- Jan 8, 2026
- Updated
- Jan 8, 2026
- Vendor
- curl
- Product
- curl
- Classifications
- CWE-297, T1557
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jan 8, 2026CVE publishedPublication date reported by the CVE source.
- Jan 8, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
Compare your product and version with the public record. A matching version still requires validation against your environment.
Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=7.58.0 <=7.58.0
- Affected versionversion=7.59.0 <=7.59.0
- Affected versionversion=7.60.0 <=7.60.0
- Affected versionversion=7.61.0 <=7.61.0
- Affected versionversion=7.61.1 <=7.61.1
- Affected versionversion=7.62.0 <=7.62.0
- Affected versionversion=7.63.0 <=7.63.0
- Affected versionversion=7.64.0 <=7.64.0
- Affected versionversion=7.64.1 <=7.64.1
- Affected versionversion=7.65.0 <=7.65.0
- Affected versionversion=7.65.1 <=7.65.1
- Affected versionversion=7.65.2 <=7.65.2
- Affected versionversion=7.65.3 <=7.65.3
- Affected versionversion=7.66.0 <=7.66.0
- Affected versionversion=7.67.0 <=7.67.0
- Affected versionversion=7.68.0 <=7.68.0
- Affected versionversion=7.69.0 <=7.69.0
- Affected versionversion=7.69.1 <=7.69.1
- Affected versionversion=7.70.0 <=7.70.0
- Affected versionversion=7.71.0 <=7.71.0
- Affected versionversion=7.71.1 <=7.71.1
- Affected versionversion=7.72.0 <=7.72.0
- Affected versionversion=7.73.0 <=7.73.0
- Affected versionversion=7.74.0 <=7.74.0
- Affected versionversion=7.75.0 <=7.75.0
- Affected versionversion=7.76.0 <=7.76.0
- Affected versionversion=7.76.1 <=7.76.1
- Affected versionversion=7.77.0 <=7.77.0
- Affected versionversion=7.78.0 <=7.78.0
- Affected versionversion=7.79.0 <=7.79.0
- Affected versionversion=7.79.1 <=7.79.1
- Affected versionversion=7.80.0 <=7.80.0
- Affected versionversion=7.81.0 <=7.81.0
- Affected versionversion=7.82.0 <=7.82.0
- Affected versionversion=7.83.0 <=7.83.0
- Affected versionversion=7.83.1 <=7.83.1
- Affected versionversion=7.84.0 <=7.84.0
- Affected versionversion=7.85.0 <=7.85.0
- Affected versionversion=7.86.0 <=7.86.0
- Affected versionversion=7.87.0 <=7.87.0
- Affected versionversion=7.88.0 <=7.88.0
- Affected versionversion=7.88.1 <=7.88.1
- Affected versionversion=8.0.0 <=8.0.0
- Affected versionversion=8.0.1 <=8.0.1
- Affected versionversion=8.10.0 <=8.10.0
- Affected versionversion=8.10.1 <=8.10.1
- Affected versionversion=8.1.0 <=8.1.0
- Affected versionversion=8.11.0 <=8.11.0
- Affected versionversion=8.11.1 <=8.11.1
- Affected versionversion=8.1.1 <=8.1.1
- Affected versionversion=8.12.0 <=8.12.0
- Affected versionversion=8.12.1 <=8.12.1
- Affected versionversion=8.1.2 <=8.1.2
- Affected versionversion=8.13.0 <=8.13.0
- Affected versionversion=8.14.0 <=8.14.0
- Affected versionversion=8.14.1 <=8.14.1
- Affected versionversion=8.15.0 <=8.15.0
- Affected versionversion=8.16.0 <=8.16.0
- Affected versionversion=8.17.0 <=8.17.0
- Affected versionversion=8.2.0 <=8.2.0
- Affected versionversion=8.2.1 <=8.2.1
- Affected versionversion=8.3.0 <=8.3.0
- Affected versionversion=8.4.0 <=8.4.0
- Affected versionversion=8.5.0 <=8.5.0
- Affected versionversion=8.6.0 <=8.6.0
- Affected versionversion=8.7.0 <=8.7.0
- Affected versionversion=8.7.1 <=8.7.1
- Affected versionversion=8.8.0 <=8.8.0
- Affected versionversion=8.9.0 <=8.9.0
- Affected versionversion=8.9.1 <=8.9.1
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- HackerOne proof-of-concept reportproof of concept · unverified
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
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