7.5

CVE-2026-12064: proto-default skips SSH verification

Modified
AliasesALPINE-CVE-2026-12064UBUNTU-CVE-2026-12064DEBIAN-CVE-2026-12064
Published 03-07-2026Last modified 15-09-2026

Vulnerability summary

CVE-2026-12064 is a high (CVSS 7.5) vulnerability in curl. EPSS estimates a 0.41% chance of exploitation in the next 30 days, higher than 35.7% of scored vulnerabilities. 1 public exploit is recorded.

Priority
Prioritisepublic exploit

Public exploit (reference, Date unknown)

Source freshness unavailable

How is this decided?
CVSS score
7.5/10
010
High · v3.1 (CVE.org)
EPSS score
0.41%
0%100%
Low · +0.01 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits1reference

Advisory lineage

Upstream 0 · Downstream 13 · Related 11
OPENSUSE-SU-2026:11230-1OPENSUSE-SU-2026:21272-1RHSA-2026:29017RHSA-2026:34975RHSA-2026:55450RHSA-2026:72506

Timeline

  1. 03-07-2026
    PublishedVulnerability first disclosed.
  2. 15-09-2026
    Last modifiedVulnerability information updated.

Description

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.

CVSS metrics

7 scores · 7 sources · 1 version

EPSS trend

Probability

0.41%

Chance of exploitation in the next 30 days

Percentile

36%

Versus all other CVEs

30-day change

Increase +0.01 pp

From 0.40% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

1 found
  • referenceUnverified

    Exploit Reference (hackerone.com)

    Maturity: unknown

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.

Chainguard11 products
  • eco-python-curl< 8.21.0-r0
  • eco-python-curl-minimal< 8.21.0-r0
  • eco-python-curl-minimal-bin< 8.21.0-r0
  • eco-python-curl-minimal-dev< 8.21.0-r0
  • eco-python-curl-minimal-doc< 8.21.0-r0
Alpine1 product
  • curl≥ 7.81.0, < 8.22.0-r0 | ≥ 7.81.0, < 8.21.0-r0
Curl1 product
  • curl≥ 7.81.0, < 8.14.2 | ≥ 8.15.0, < 8.16.1 | ≥ 8.17.0, < 8.20.1 | ≥ 18270893abdb19f0ca170c118f8a2847dbd304be, < ab3bb8cd8be8f9d4acb97da0418abc279182041e | 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 | 8.11.0 | 8.10.1 | 8.10.0 | 8.9.1 | 8.9.0 | 8.8.0 | 8.7.1 | 8.7.0 | 8.6.0 | 8.5.0 | 8.4.0 | 8.3.0 | 8.2.1 | 8.2.0 | 8.1.2 | 8.1.1 | 8.1.0 | 8.0.1 | 8.0.0 | 7.88.1 | 7.88.0 | 7.87.0 | 7.86.0 | 7.85.0 | 7.84.0 | 7.83.1 | 7.83.0 | 7.82.0 | 7.81.0
Debian1 product
  • curlAll versions (No fix recorded) | < 8.21.0~rc3-1
Haxx1 product
  • curl≥ 7.81.0, < 8.21.0
Ubuntu1 product
  • curl< 8.14.1-2ubuntu1.5 | < 8.18.0-1ubuntu2.3
Wolfi1 product
  • libcurl4All versions (No fix recorded)

7 vendors · 17 products

References

11 links
Show all 11 references