# CVE-2026-6253 ## Summary - **CVE ID:** CVE-2026-6253 - **Severity:** MEDIUM - **CVSS Score:** 5.9 (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H) - **CWE:** CWE-522 - **Published:** May 13, 2026 - **Last Modified:** Sep 17, 2026 ## Description 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 ## Affected Products - curl — curl (8.19.0) - curl — curl (8.18.0) - curl — curl (8.17.0) - curl — curl (8.16.0) - curl — curl (8.15.0) - curl — curl (8.14.1) - curl — curl (8.14.0) - curl — curl (8.13.0) - curl — curl (8.12.1) - curl — curl (8.12.0) - curl — curl (8.11.1) - curl — curl (8.11.0) - curl — curl (8.10.1) - curl — curl (8.10.0) - curl — curl (8.9.1) - curl — curl (8.9.0) - curl — curl (8.8.0) - curl — curl (8.7.1) - curl — curl (8.7.0) - curl — curl (8.6.0) - curl — curl (8.5.0) - curl — curl (8.4.0) - curl — curl (8.3.0) - curl — curl (8.2.1) - curl — curl (8.2.0) - curl — curl (8.1.2) - curl — curl (8.1.1) - curl — curl (8.1.0) - curl — curl (8.0.1) - curl — curl (8.0.0) - curl — curl (7.88.1) - curl — curl (7.88.0) - curl — curl (7.87.0) - curl — curl (7.86.0) - curl — curl (7.85.0) - curl — curl (7.84.0) - curl — curl (7.83.1) - curl — curl (7.83.0) - curl — curl (7.82.0) - curl — curl (7.81.0) - curl — curl (7.80.0) - curl — curl (7.79.1) - curl — curl (7.79.0) - curl — curl (7.78.0) - curl — curl (7.77.0) - curl — curl (7.76.1) - curl — curl (7.76.0) - curl — curl (7.75.0) - curl — curl (7.74.0) - curl — curl (7.73.0) - curl — curl (7.72.0) - curl — curl (7.71.1) - curl — curl (7.71.0) - curl — curl (7.70.0) - curl — curl (7.69.1) - curl — curl (7.69.0) - curl — curl (7.68.0) - curl — curl (7.67.0) - curl — curl (7.66.0) - curl — curl (7.65.3) - curl — curl (7.65.2) - curl — curl (7.65.1) - curl — curl (7.65.0) - curl — curl (7.64.1) - curl — curl (7.64.0) - curl — curl (7.63.0) - curl — curl (7.62.0) - curl — curl (7.61.1) - curl — curl (7.61.0) - curl — curl (7.60.0) - curl — curl (7.59.0) - curl — curl (7.58.0) - curl — curl (7.57.0) - curl — curl (7.56.1) - curl — curl (7.56.0) - curl — curl (7.55.1) - curl — curl (7.55.0) - curl — curl (7.54.1) - curl — curl (7.54.0) - curl — curl (7.53.1) - curl — curl (7.53.0) - curl — curl (7.52.1) - curl — curl (7.52.0) - curl — curl (7.51.0) - curl — curl (7.50.3) - curl — curl (7.50.2) - curl — curl (7.50.1) - curl — curl (7.50.0) - curl — curl (7.49.1) - curl — curl (7.49.0) - curl — curl (7.48.0) - curl — curl (7.47.1) - curl — curl (7.47.0) - curl — curl (7.46.0) - curl — curl (7.45.0) - curl — curl (7.44.0) - curl — curl (7.43.0) - curl — curl (7.42.1) - curl — curl (7.42.0) - curl — curl (7.41.0) - curl — curl (7.40.0) - curl — curl (7.39.0) - curl — curl (7.38.0) - curl — curl (7.37.1) - curl — curl (7.37.0) - curl — curl (7.36.0) - curl — curl (7.35.0) - curl — curl (7.34.0) - curl — curl (7.33.0) - curl — curl (7.32.0) - curl — curl (7.31.0) - curl — curl (7.30.0) - curl — curl (7.29.0) - curl — curl (7.28.1) - curl — curl (7.28.0) - curl — curl (7.27.0) - curl — curl (7.26.0) - curl — curl (7.25.0) - curl — curl (7.24.0) - curl — curl (7.23.1) - curl — curl (7.23.0) - curl — curl (7.22.0) - curl — curl (7.21.7) - curl — curl (7.21.6) - curl — curl (7.21.5) - curl — curl (7.21.4) - curl — curl (7.21.3) - curl — curl (7.21.2) - curl — curl (7.21.1) - curl — curl (7.21.0) - curl — curl (7.20.1) - curl — curl (7.20.0) - curl — curl (7.19.7) - curl — curl (7.19.6) - curl — curl (7.19.5) - curl — curl (7.19.4) - curl — curl (7.19.3) - curl — curl (7.19.2) - curl — curl (7.19.1) - curl — curl (7.19.0) - curl — curl (7.18.2) - curl — curl (7.18.1) - curl — curl (7.18.0) - curl — curl (7.17.1) - curl — curl (7.17.0) - curl — curl (7.16.4) - curl — curl (7.16.3) - curl — curl (7.16.2) - curl — curl (7.16.1) - curl — curl (7.16.0) - curl — curl (7.15.5) - curl — curl (7.15.4) - curl — curl (7.15.3) - curl — curl (7.15.2) - curl — curl (7.15.1) - curl — curl (7.15.0) - curl — curl (7.14.1) - curl — curl (3b60bb725913ce7339aefef0a14b12df4c24db60) ## References - [CNA](https://curl.se/docs/CVE-2026-6253.json) - [CNA](https://curl.se/docs/CVE-2026-6253.html) - [CNA](https://hackerone.com/reports/3669637) - [CVE](http://www.openwall.com/lists/oss-security/2026/04/29/11) ## Exploitation Prediction (EPSS) - **EPSS Score:** 0.72% - **EPSS Percentile:** 52.3 --- _Exported from OnDuty AI Vulnerability Intelligence on 2026-09-18._