CVE-2026-6253: curl · Insufficiently Protected Credentials
Affects curlSource GCVE Database
Not known to be exploited · CVSS 5.9 Medium.
Data as of 11 Nov 2026, 23:18 UTC
Thin evidence
One scorer or none| CISA-ADP | CVSS 3.1 | 5.9 |
|---|
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 13 May 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 11 Nov 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| curl curl | Affected
| Fixed in– |
AI-suggested
Until a fix is available, users should carefully review proxy configurations to avoid scenarios where different proxies with differing credential requirements are used for different URL schemes, especially when redirects are involved.
Description
CVE-2026-6253 is a vulnerability in curl where credentials intended for a first proxy may be mistakenly sent to a second proxy under certain redirect conditions. This occurs when curl is configured to use different proxies for different URL schemes, the first proxy requires credentials, the second proxy does not, and a redirect causes curl to switch proxies. The vulnerability has a medium severity rating with a CVSS score of 5.9.