CVE-2026-12064: proto-default skips SSH verification
Vendor fix available · Affected: curl · Exploitation: unlikely (under 1%)
Not in CyberSIXT coverage yet: no article names this CVE. This page shows the public record.
Higher than 36% of scored CVEs
DescriptionCVE.org
When a user invokes curl using a schemeless URL combined with `--proto-default` sftp (or scp), a disconnect occurs between the tool layer and libcurl. The tool layer incorrectly infers the URL scheme, which erroneously bypasses the initialization of critical SSH security options like CURLOPT_SSH_HOST_PUBLIC_KEY_SHA256 and CURLOPT_SSH_KNOWNHOSTS. Conversely, the libcurl runtime successfully honors CURLOPT_DEFAULT_PROTOCOL and establishes the connection via SFTP/SCP as specified. Because the tool layer skipped the security configuration, these SSH host verification options are silently omitted, causing curl to connect to an unverified SSH remote host without throwing an error.
Affected products3
From the CVE record. A product or version that is not listed is unknown, not unaffected.
- curl · curlfrom 7.81.0 before 8.14.2; from 8.15.0 before 8.16.1; from 8.17.0 before 8.20.1
- curl · curlVersions not stated
- curl · curl8.20.0; 8.19.0; 8.18.0; 8.17.0; 8.16.0; 8.15.0 and 35 more
On the Atlas
Every published CVE is on the CyberSIXT Atlas, grouped by weakness, vendor and month.
- Exploitation
- Unlikely (under 1%). EPSS under 1%, or no score yet.
- CISA KEV
- Not listed
- Public check
- No public nuclei template
- Vendor
- curl
- Published
- July 2026
- Bounty reports
- 3 disclosed on HackerOne
Disclosed bug bounty reports about CVE-2026-12064
The reports on HackerOne that name this CVE, with HackerOne's own outcome. Titles and metadata only.
- curl tool: --hsts is ignored for a schemeless URL starting with a slash under --proto-default httpcurl · 2026 · low severityInformative
- CVE-2026-12064: proto-default skips SSH verificationcurl · 2026 · low severityValid
- CVE-2026-86410: redirect to SFTP or SCP bypasses host verificationcurl · 2026Valid
CoverageNo articles yet
No CyberSIXT article names CVE-2026-12064 yet, so there is no coverage timeline, action brief or change log for it. Everything on this page comes from the public CVE record, CISA KEV, EPSS and the nuclei template index. Search the archive or see the CVEs in the news.