leaking host credentials to HTTP proxy
Affects curl 7.10.8 through 8.22.0 when the HTTP proxy answers CONNECT with 401 WWW-Authenticate instead of 407. curl rates it Low. Fixed in 8.23.0.
- Published
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- How many real-world setups can hit the bug, from the vendor's advisory and CISA data. It does not know your setup.What do these mean? →
- Unclear
- The rating the maker of the software gives it. Shown when it differs from the CVSS level.What do these mean? →
- Low (curl)
- Fix
- Fixed in 8.14.3, 8.16.2, 8.20.2, 8.23.0
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
- Exploitation: poc
- Automatable: yes
- Technical impact: total
Summary
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:`.
Timeline
- CVE published
- CISA SSVC assessment
Exploitation: poc · Automatable: yes · Technical impact: total
- Record last updated
Affected versions
- curl curl
From 8.22.0 · through 8.22.0; From 8.21.0 · through 8.21.0; From 8.20.0 · through 8.20.0; From 8.19.0 · through 8.19.0; From 8.18.0 · through 8.18.0; From 8.17.0 · through 8.17.0; From 8.16.0 · through 8.16.0; From 8.15.0 · through 8.15.0; From 8.14.1 · through 8.14.1; From 8.14.0 · through 8.14.0; From 8.13.0 · through 8.13.0; From 8.12.1 · through 8.12.1; From 8.12.0 · through 8.12.0; From 8.11.1 · through 8.11.1; From 8.11.0 · through 8.11.0; From 8.10.1 · through 8.10.1; From 8.10.0 · through 8.10.0; From 8.9.1 · through 8.9.1; From 8.9.0 · through 8.9.0; From 8.8.0 · through 8.8.0; From 8.7.1 · through 8.7.1; From 8.7.0 · through 8.7.0; From 8.6.0 · through 8.6.0; From 8.5.0 · through 8.5.0; From 8.4.0 · through 8.4.0; From 8.3.0 · through 8.3.0; From 8.2.1 · through 8.2.1; From 8.2.0 · through 8.2.0; From 8.1.2 · through 8.1.2; From 8.1.1 · through 8.1.1; From 8.1.0 · through 8.1.0; From 8.0.1 · through 8.0.1; From 8.0.0 · through 8.0.0; From 7.88.1 · through 7.88.1; From 7.88.0 · through 7.88.0; From 7.87.0 · through 7.87.0; From 7.86.0 · through 7.86.0; From 7.85.0 · through 7.85.0; From 7.84.0 · through 7.84.0; From 7.83.1 · through 7.83.1; From 7.83.0 · through 7.83.0; From 7.82.0 · through 7.82.0; From 7.81.0 · through 7.81.0; From 7.80.0 · through 7.80.0; From 7.79.1 · through 7.79.1; From 7.79.0 · through 7.79.0; From 7.78.0 · through 7.78.0; From 7.77.0 · through 7.77.0; From 7.76.1 · through 7.76.1; From 7.76.0 · through 7.76.0; From 7.75.0 · through 7.75.0; From 7.74.0 · through 7.74.0; From 7.73.0 · through 7.73.0; From 7.72.0 · through 7.72.0; From 7.71.1 · through 7.71.1; From 7.71.0 · through 7.71.0; From 7.70.0 · through 7.70.0; From 7.69.1 · through 7.69.1; From 7.69.0 · through 7.69.0; From 7.68.0 · through 7.68.0; From 7.67.0 · through 7.67.0; From 7.66.0 · through 7.66.0; From 7.65.3 · through 7.65.3; From 7.65.2 · through 7.65.2; From 7.65.1 · through 7.65.1; From 7.65.0 · through 7.65.0; From 7.64.1 · through 7.64.1; From 7.64.0 · through 7.64.0; From 7.63.0 · through 7.63.0; From 7.62.0 · through 7.62.0; From 7.61.1 · through 7.61.1; From 7.61.0 · through 7.61.0; From 7.60.0 · through 7.60.0; From 7.59.0 · through 7.59.0; From 7.58.0 · through 7.58.0; From 7.57.0 · through 7.57.0; From 7.56.1 · through 7.56.1; From 7.56.0 · through 7.56.0; From 7.55.1 · through 7.55.1; From 7.55.0 · through 7.55.0; From 7.54.1 · through 7.54.1; From 7.54.0 · through 7.54.0; From 7.53.1 · through 7.53.1; From 7.53.0 · through 7.53.0; From 7.52.1 · through 7.52.1; From 7.52.0 · through 7.52.0; From 7.51.0 · through 7.51.0; From 7.50.3 · through 7.50.3; From 7.50.2 · through 7.50.2; From 7.50.1 · through 7.50.1; From 7.50.0 · through 7.50.0; From 7.49.1 · through 7.49.1; From 7.49.0 · through 7.49.0; From 7.48.0 · through 7.48.0; From 7.47.1 · through 7.47.1; From 7.47.0 · through 7.47.0; From 7.46.0 · through 7.46.0; From 7.45.0 · through 7.45.0; From 7.44.0 · through 7.44.0; From 7.43.0 · through 7.43.0; From 7.42.1 · through 7.42.1; From 7.42.0 · through 7.42.0; From 7.41.0 · through 7.41.0; From 7.40.0 · through 7.40.0; From 7.39.0 · through 7.39.0; From 7.38.0 · through 7.38.0; From 7.37.1 · through 7.37.1; From 7.37.0 · through 7.37.0; From 7.36.0 · through 7.36.0; From 7.35.0 · through 7.35.0; From 7.34.0 · through 7.34.0; From 7.33.0 · through 7.33.0; From 7.32.0 · through 7.32.0; From 7.31.0 · through 7.31.0; From 7.30.0 · through 7.30.0; From 7.29.0 · through 7.29.0; From 7.28.1 · through 7.28.1; From 7.28.0 · through 7.28.0; From 7.27.0 · through 7.27.0; From 7.26.0 · through 7.26.0; From 7.25.0 · through 7.25.0; From 7.24.0 · through 7.24.0; From 7.23.1 · through 7.23.1; From 7.23.0 · through 7.23.0; From 7.22.0 · through 7.22.0; From 7.21.7 · through 7.21.7; From 7.21.6 · through 7.21.6; From 7.21.5 · through 7.21.5; From 7.21.4 · through 7.21.4; From 7.21.3 · through 7.21.3; From 7.21.2 · through 7.21.2; From 7.21.1 · through 7.21.1; From 7.21.0 · through 7.21.0; From 7.20.1 · through 7.20.1; From 7.20.0 · through 7.20.0; From 7.19.7 · through 7.19.7; From 7.19.6 · through 7.19.6; From 7.19.5 · through 7.19.5; From 7.19.4 · through 7.19.4; From 7.19.3 · through 7.19.3; From 7.19.2 · through 7.19.2; From 7.19.1 · through 7.19.1; From 7.19.0 · through 7.19.0; From 7.18.2 · through 7.18.2; From 7.18.1 · through 7.18.1; From 7.18.0 · through 7.18.0; From 7.17.1 · through 7.17.1; From 7.17.0 · through 7.17.0; From 7.16.4 · through 7.16.4; From 7.16.3 · through 7.16.3; From 7.16.2 · through 7.16.2; From 7.16.1 · through 7.16.1; From 7.16.0 · through 7.16.0; From 7.15.5 · through 7.15.5; From 7.15.4 · through 7.15.4; From 7.15.3 · through 7.15.3; From 7.15.2 · through 7.15.2; From 7.15.1 · through 7.15.1; From 7.15.0 · through 7.15.0; From 7.14.1 · through 7.14.1; From 7.14.0 · through 7.14.0; From 7.13.2 · through 7.13.2; From 7.13.1 · through 7.13.1; From 7.13.0 · through 7.13.0; From 7.12.3 · through 7.12.3; From 7.12.2 · through 7.12.2; From 7.12.1 · through 7.12.1; From 7.12.0 · through 7.12.0; From 7.11.2 · through 7.11.2; From 7.11.1 · through 7.11.1; From 7.11.0 · through 7.11.0; From 7.10.8 · through 7.10.8
References 3
hackerone.com
Questions about CVE-2026-86414
What does this mean?
When libcurl connects through an HTTP proxy, a malicious proxy can take the origin server's credentials, either a Basic password or a Negotiate/Kerberos ticket, because libcurl sends them to the proxy itself.Source: curl.se, curl.se
Am I affected, and how do I check?
Affected versions are curl 7.10.8 up to and including 8.22.0. The bug needs an HTTP proxy that replies to the CONNECT request with a 401 WWW-Authenticate challenge instead of the expected 407 Proxy-Authenticate. Check the installed version with curl --version and check whether a proxy is set in the configuration or environment.Source: curl.se, curl.se
What should I do about it?
Upgrade curl to 8.23.0. For older maintained branches, the advisory lists fixed releases 8.14.3, 8.16.2, and 8.20.2.Source: curl.se, curl.se
Is it being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. CISA's SSVC assessment notes a proof of concept exists. No public exploit code is tracked.Source: cve.now feed data