CVE-2026-9547 (GCVE-0-2026-9547)
Vulnerability from cvelistv5 – Published: 2026-07-03 06:18 – Updated: 2026-07-03 06:18
VLAI?
Title
SSH improper host validation
Summary
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.
Severity ?
No CVSS data available.
Assigner
References
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| curl | curl |
Affected:
8.20.0 , ≤ 8.20.0
(semver)
Affected: 8.19.0 , ≤ 8.19.0 (semver) Affected: 8.18.0 , ≤ 8.18.0 (semver) Affected: 8.17.0 , ≤ 8.17.0 (semver) Affected: 8.16.0 , ≤ 8.16.0 (semver) Affected: 8.15.0 , ≤ 8.15.0 (semver) Affected: 8.14.1 , ≤ 8.14.1 (semver) Affected: 8.14.0 , ≤ 8.14.0 (semver) Affected: 8.13.0 , ≤ 8.13.0 (semver) Affected: 8.12.1 , ≤ 8.12.1 (semver) Affected: 8.12.0 , ≤ 8.12.0 (semver) Affected: 8.11.1 , ≤ 8.11.1 (semver) Affected: 8.11.0 , ≤ 8.11.0 (semver) Affected: 8.10.1 , ≤ 8.10.1 (semver) Affected: 8.10.0 , ≤ 8.10.0 (semver) Affected: 8.9.1 , ≤ 8.9.1 (semver) Affected: 8.9.0 , ≤ 8.9.0 (semver) Affected: 8.8.0 , ≤ 8.8.0 (semver) Affected: 8.7.1 , ≤ 8.7.1 (semver) Affected: 8.7.0 , ≤ 8.7.0 (semver) Affected: 8.6.0 , ≤ 8.6.0 (semver) Affected: 8.5.0 , ≤ 8.5.0 (semver) Affected: 8.4.0 , ≤ 8.4.0 (semver) Affected: 8.3.0 , ≤ 8.3.0 (semver) Affected: 8.2.1 , ≤ 8.2.1 (semver) Affected: 8.2.0 , ≤ 8.2.0 (semver) Affected: 8.1.2 , ≤ 8.1.2 (semver) Affected: 8.1.1 , ≤ 8.1.1 (semver) Affected: 8.1.0 , ≤ 8.1.0 (semver) Affected: 8.0.1 , ≤ 8.0.1 (semver) Affected: 8.0.0 , ≤ 8.0.0 (semver) Affected: 7.88.1 , ≤ 7.88.1 (semver) Affected: 7.88.0 , ≤ 7.88.0 (semver) Affected: 7.87.0 , ≤ 7.87.0 (semver) Affected: 7.86.0 , ≤ 7.86.0 (semver) Affected: 7.85.0 , ≤ 7.85.0 (semver) Affected: 7.84.0 , ≤ 7.84.0 (semver) Affected: 7.83.1 , ≤ 7.83.1 (semver) Affected: 7.83.0 , ≤ 7.83.0 (semver) Affected: 7.82.0 , ≤ 7.82.0 (semver) Affected: 7.81.0 , ≤ 7.81.0 (semver) Affected: 7.80.0 , ≤ 7.80.0 (semver) Affected: 7.79.1 , ≤ 7.79.1 (semver) Affected: 7.79.0 , ≤ 7.79.0 (semver) Affected: 7.78.0 , ≤ 7.78.0 (semver) Affected: 7.77.0 , ≤ 7.77.0 (semver) Affected: 7.76.1 , ≤ 7.76.1 (semver) Affected: 7.76.0 , ≤ 7.76.0 (semver) Affected: 7.75.0 , ≤ 7.75.0 (semver) Affected: 7.74.0 , ≤ 7.74.0 (semver) Affected: 7.73.0 , ≤ 7.73.0 (semver) Affected: 7.72.0 , ≤ 7.72.0 (semver) Affected: 7.71.1 , ≤ 7.71.1 (semver) Affected: 7.71.0 , ≤ 7.71.0 (semver) Affected: 7.70.0 , ≤ 7.70.0 (semver) Affected: 7.69.1 , ≤ 7.69.1 (semver) Affected: 7.69.0 , ≤ 7.69.0 (semver) |
Credits
Joshua Rogers (Aisle Research)
Joshua Rogers (Aisle Research)
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"lessThanOrEqual": "8.1.2",
"status": "affected",
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"lessThanOrEqual": "8.1.1",
"status": "affected",
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{
"lessThanOrEqual": "8.1.0",
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{
"lessThanOrEqual": "8.0.1",
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"lessThanOrEqual": "8.0.0",
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{
"lessThanOrEqual": "7.88.1",
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"lessThanOrEqual": "7.84.0",
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"lessThanOrEqual": "7.83.1",
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"credits": [
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"lang": "en",
"type": "finder",
"value": "Joshua Rogers (Aisle Research)"
},
{
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"value": "Joshua Rogers (Aisle Research)"
}
],
"descriptions": [
{
"lang": "en",
"value": "When a libcurl-based application performs transfers via `SCP://` or `SFTP://`\nand utilizes the `CURLOPT_SSH_KEYFUNCTION` callback, it may silently accept an\nuntrusted server. This vulnerability occurs when a server presents a host key\ntype that does not match the specific key type already recorded for that host\nin the `known_hosts` file. Instead of rejecting the mismatch, the callback\nmechanism fails to properly enforce the restriction, allowing the connection\nto succeed without warning and risking a potential man-in-the-middle attack."
}
],
"problemTypes": [
{
"descriptions": [
{
"description": "CWE-297 Improper Validation of Certificate with Host Mismatch",
"lang": "en"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-07-03T06:18:44.499Z",
"orgId": "2499f714-1537-4658-8207-48ae4bb9eae9",
"shortName": "curl"
},
"references": [
{
"name": "json",
"url": "https://curl.se/docs/CVE-2026-9547.json"
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{
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"url": "https://curl.se/docs/CVE-2026-9547.html"
},
{
"name": "issue",
"url": "https://hackerone.com/reports/3751712"
}
],
"title": "SSH improper host validation"
}
},
"cveMetadata": {
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"datePublished": "2026-07-03T06:18:44.499Z",
"dateReserved": "2026-05-26T06:45:27.665Z",
"dateUpdated": "2026-07-03T06:18:44.499Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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