CVE-2026-6253
🔶 mediumSummary
curl might erroneously pass on credentials for a first proxy to a second proxy. This can happen when the following conditions are true: 1. curl is setup to use specific different proxies for different URL schemes 2. the first proxy needs credentials 3. the second proxy uses no credentials 4. while using the first proxy (using say `http://`), curl is asked to follow a redirect to a URL using another scheme (say `https://`), accessed using a second, different, proxy
CVSS Score
5.9
Medium
EPSS Score
0.7
Exploit Probability
Published Date
2026-05-13
First Seen: 2026-05-17
📊 Relative Risk Intelligence
This CVE is Lower Risk - more severe than 32.1% of all 365,891 vulnerabilities in our database.
#248,423
Below average severity
Severity Percentile
🎯 CISA SSVC Assessment Updated: May 13, 2026
🔍 Exploitation Status
Poc
Proof-of-concept available
⚙️ Automatable
NO
Requires human interaction
💥 Technical Impact
Partial
Limited system impact
🏆 Discovered By
Dwij Mehta (O2 Lab
Texas A&M University)
Daniel Stenberg (remediation developer)
SSVC data provided by
CISA
Last Modified
2026-09-15
Source
NVD 🔗
CVSS Vector 3.1
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
CWE IDs (Weakness Types)