CVE-2026-86414: leaking host credentials to HTTP proxy

Published Oct 14, 2026
·
Updated

An HTTP proxy can trick libcurl into sending the origin's credentials (Basic password, or a Negotiate/Kerberos ticket) to the proxy itself, by answering the CONNECT tunnel request with 401 WWW-Authenticate: instead of the expected 407 Proxy-Authenticate:.

Affected Software

16 affected componentsFixes available
alpine/curl<8.23.0-r0
8.23.0-r0
alpine/curl<8.23.0-r0
8.23.0-r0
debian/curl*
debian/curl*
debian/curl*
debian/curl<=7.88.1-10+deb12u15, <=7.88.1-10+deb12u5, <=8.14.1-2+deb13u5, <=8.14.1-2+deb13u7, <=8.22.0-1
8.23.0-1
ubuntu/curl<7.35.0-1ubuntu2.20+esm24
7.35.0-1ubuntu2.20+esm24
ubuntu/curl<7.47.0-1ubuntu2.19+esm21
7.47.0-1ubuntu2.19+esm21
ubuntu/curl<7.58.0-2ubuntu3.24+esm15
7.58.0-2ubuntu3.24+esm15
ubuntu/curl<7.68.0-1ubuntu2.25+esm10
7.68.0-1ubuntu2.25+esm10
ubuntu/curl<7.81.0-1ubuntu1.30
7.81.0-1ubuntu1.30
ubuntu/curl<8.5.0-2ubuntu10.16
8.5.0-2ubuntu10.16
ubuntu/curl<8.20.0-2ubuntu11.1
8.20.0-2ubuntu11.1
ubuntu/curl<8.18.0-1ubuntu2.8
8.18.0-1ubuntu2.8
All of the following
azurelinux/curl<8.11.1-13
8.11.1-13
Microsoft Azure Linux=3.0

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade alpine/curl to a version that resolves this vulnerability.

    Fixed in 8.23.0-r0
  2. Upgrade

    Upgrade debian/curl to a version that resolves this vulnerability.

    Fixed in 8.23.0-1
  3. Upgrade

    Upgrade ubuntu/curl to a version that resolves this vulnerability.

    Fixed in 7.35.0-1ubuntu2.20+esm24
  4. Upgrade

    Upgrade ubuntu/curl to a version that resolves this vulnerability.

    Fixed in 7.47.0-1ubuntu2.19+esm21
  5. Upgrade

    Upgrade ubuntu/curl to a version that resolves this vulnerability.

    Fixed in 7.58.0-2ubuntu3.24+esm15
  6. Upgrade

    Upgrade ubuntu/curl to a version that resolves this vulnerability.

    Fixed in 7.68.0-1ubuntu2.25+esm10
  7. Upgrade

    Upgrade ubuntu/curl to a version that resolves this vulnerability.

    Fixed in 7.81.0-1ubuntu1.30
  8. Upgrade

    Upgrade ubuntu/curl to a version that resolves this vulnerability.

    Fixed in 8.5.0-2ubuntu10.16
  9. Upgrade

    Upgrade ubuntu/curl to a version that resolves this vulnerability.

    Fixed in 8.20.0-2ubuntu11.1
  10. Upgrade

    Upgrade ubuntu/curl to a version that resolves this vulnerability.

    Fixed in 8.18.0-1ubuntu2.8
  11. Upgrade

    Upgrade azurelinux/curl to a version that resolves this vulnerability.

    Fixed in 8.11.1-13

Event History

Oct 14, 2026
CVE Published
via OSV·06:00 AM
Data Sourced
via OSV·06:00 AM
DescriptionSeverityAffected Software
Oct 20, 2026
CVE Published
via MITRE·08:07 PM
Data Sourced
via MITRE·08:07 PM
DescriptionWeakness
Data Sourced
via NVD·09:17 PM
DescriptionSeverityWeakness
Oct 23, 2026
Data Sourced
via Microsoft·08:04 AM
DescriptionSeverityWeakness
Data Sourced
via Microsoft·08:04 AM
Affected Software

Company

Resources

Contact

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