CVE-2026-6253

EUVD-2026-29927

13.05.2026, 13:01

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

Provider	Type	Base Score	Atk. Vector	Atk. Complexity	Priv. Required	Vector
curl	CNA	5.9 MEDIUM	NETWORK	HIGH	NONE	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

Base Score

CVSS 3.x

EPSS Score

Percentile: 3%

Early Detection

Affected products identified ahead of NVD analysis through intelligence sources.

Vendor	Product	Version	Source
curl	curl	𝑥 ≤ 8.19.0	CNA
curl	curl	𝑥 ≤ 8.18.0	CNA
curl	curl	𝑥 ≤ 8.17.0	CNA
curl	curl	𝑥 ≤ 8.16.0	CNA
curl	curl	𝑥 ≤ 8.15.0	CNA
curl	curl	𝑥 ≤ 8.14.1	CNA
curl	curl	𝑥 ≤ 8.14.0	CNA
curl	curl	𝑥 ≤ 8.13.0	CNA
curl	curl	𝑥 ≤ 8.12.1	CNA
curl	curl	𝑥 ≤ 8.12.0	CNA
curl	curl	𝑥 ≤ 8.11.1	CNA
curl	curl	𝑥 ≤ 8.11.0	CNA
curl	curl	𝑥 ≤ 8.10.1	CNA
curl	curl	𝑥 ≤ 8.10.0	CNA
curl	curl	𝑥 ≤ 8.9.1	CNA
curl	curl	𝑥 ≤ 8.9.0	CNA
curl	curl	𝑥 ≤ 8.8.0	CNA
curl	curl	𝑥 ≤ 8.7.1	CNA
curl	curl	𝑥 ≤ 8.7.0	CNA
curl	curl	𝑥 ≤ 8.6.0	CNA
curl	curl	𝑥 ≤ 8.5.0	CNA
curl	curl	𝑥 ≤ 8.4.0	CNA
curl	curl	𝑥 ≤ 8.3.0	CNA
curl	curl	𝑥 ≤ 8.2.1	CNA
curl	curl	𝑥 ≤ 8.2.0	CNA
curl	curl	𝑥 ≤ 8.1.2	CNA
curl	curl	𝑥 ≤ 8.1.1	CNA
curl	curl	𝑥 ≤ 8.1.0	CNA
curl	curl	𝑥 ≤ 8.0.1	CNA
curl	curl	𝑥 ≤ 8.0.0	CNA
curl	curl	𝑥 ≤ 7.88.1	CNA
curl	curl	𝑥 ≤ 7.88.0	CNA
curl	curl	𝑥 ≤ 7.87.0	CNA
curl	curl	𝑥 ≤ 7.86.0	CNA
curl	curl	𝑥 ≤ 7.85.0	CNA
curl	curl	𝑥 ≤ 7.84.0	CNA
curl	curl	𝑥 ≤ 7.83.1	CNA
curl	curl	𝑥 ≤ 7.83.0	CNA
curl	curl	𝑥 ≤ 7.82.0	CNA
curl	curl	𝑥 ≤ 7.81.0	CNA
curl	curl	𝑥 ≤ 7.80.0	CNA
curl	curl	𝑥 ≤ 7.79.1	CNA
curl	curl	𝑥 ≤ 7.79.0	CNA
curl	curl	𝑥 ≤ 7.78.0	CNA
curl	curl	𝑥 ≤ 7.77.0	CNA
curl	curl	𝑥 ≤ 7.76.1	CNA
curl	curl	𝑥 ≤ 7.76.0	CNA
curl	curl	𝑥 ≤ 7.75.0	CNA
curl	curl	𝑥 ≤ 7.74.0	CNA
curl	curl	𝑥 ≤ 7.73.0	CNA
curl	curl	𝑥 ≤ 7.72.0	CNA
curl	curl	𝑥 ≤ 7.71.1	CNA
curl	curl	𝑥 ≤ 7.71.0	CNA
curl	curl	𝑥 ≤ 7.70.0	CNA
curl	curl	𝑥 ≤ 7.69.1	CNA
curl	curl	𝑥 ≤ 7.69.0	CNA
curl	curl	𝑥 ≤ 7.68.0	CNA
curl	curl	𝑥 ≤ 7.67.0	CNA
curl	curl	𝑥 ≤ 7.66.0	CNA
curl	curl	𝑥 ≤ 7.65.3	CNA
curl	curl	𝑥 ≤ 7.65.2	CNA
curl	curl	𝑥 ≤ 7.65.1	CNA
curl	curl	𝑥 ≤ 7.65.0	CNA
curl	curl	𝑥 ≤ 7.64.1	CNA
curl	curl	𝑥 ≤ 7.64.0	CNA
curl	curl	𝑥 ≤ 7.63.0	CNA
curl	curl	𝑥 ≤ 7.62.0	CNA
curl	curl	𝑥 ≤ 7.61.1	CNA
curl	curl	𝑥 ≤ 7.61.0	CNA
curl	curl	𝑥 ≤ 7.60.0	CNA
curl	curl	𝑥 ≤ 7.59.0	CNA
curl	curl	𝑥 ≤ 7.58.0	CNA
curl	curl	𝑥 ≤ 7.57.0	CNA
curl	curl	𝑥 ≤ 7.56.1	CNA
curl	curl	𝑥 ≤ 7.56.0	CNA
curl	curl	𝑥 ≤ 7.55.1	CNA
curl	curl	𝑥 ≤ 7.55.0	CNA
curl	curl	𝑥 ≤ 7.54.1	CNA
curl	curl	𝑥 ≤ 7.54.0	CNA
curl	curl	𝑥 ≤ 7.53.1	CNA
curl	curl	𝑥 ≤ 7.53.0	CNA
curl	curl	𝑥 ≤ 7.52.1	CNA
curl	curl	𝑥 ≤ 7.52.0	CNA
curl	curl	𝑥 ≤ 7.51.0	CNA
curl	curl	𝑥 ≤ 7.50.3	CNA
curl	curl	𝑥 ≤ 7.50.2	CNA
curl	curl	𝑥 ≤ 7.50.1	CNA
curl	curl	𝑥 ≤ 7.50.0	CNA
curl	curl	𝑥 ≤ 7.49.1	CNA
curl	curl	𝑥 ≤ 7.49.0	CNA
curl	curl	𝑥 ≤ 7.48.0	CNA
curl	curl	𝑥 ≤ 7.47.1	CNA
curl	curl	𝑥 ≤ 7.47.0	CNA
curl	curl	𝑥 ≤ 7.46.0	CNA
curl	curl	𝑥 ≤ 7.45.0	CNA
curl	curl	𝑥 ≤ 7.44.0	CNA
curl	curl	𝑥 ≤ 7.43.0	CNA
curl	curl	𝑥 ≤ 7.42.1	CNA
curl	curl	𝑥 ≤ 7.42.0	CNA
curl	curl	𝑥 ≤ 7.41.0	CNA
curl	curl	𝑥 ≤ 7.40.0	CNA
curl	curl	𝑥 ≤ 7.39.0	CNA
curl	curl	𝑥 ≤ 7.38.0	CNA
curl	curl	𝑥 ≤ 7.37.1	CNA
curl	curl	𝑥 ≤ 7.37.0	CNA
curl	curl	𝑥 ≤ 7.36.0	CNA
curl	curl	𝑥 ≤ 7.35.0	CNA
curl	curl	𝑥 ≤ 7.34.0	CNA
curl	curl	𝑥 ≤ 7.33.0	CNA
curl	curl	𝑥 ≤ 7.32.0	CNA
curl	curl	𝑥 ≤ 7.31.0	CNA
curl	curl	𝑥 ≤ 7.30.0	CNA
curl	curl	𝑥 ≤ 7.29.0	CNA
curl	curl	𝑥 ≤ 7.28.1	CNA
curl	curl	𝑥 ≤ 7.28.0	CNA
curl	curl	𝑥 ≤ 7.27.0	CNA
curl	curl	𝑥 ≤ 7.26.0	CNA
curl	curl	𝑥 ≤ 7.25.0	CNA
curl	curl	𝑥 ≤ 7.24.0	CNA
curl	curl	𝑥 ≤ 7.23.1	CNA
curl	curl	𝑥 ≤ 7.23.0	CNA
curl	curl	𝑥 ≤ 7.22.0	CNA
curl	curl	𝑥 ≤ 7.21.7	CNA
curl	curl	𝑥 ≤ 7.21.6	CNA
curl	curl	𝑥 ≤ 7.21.5	CNA
curl	curl	𝑥 ≤ 7.21.4	CNA
curl	curl	𝑥 ≤ 7.21.3	CNA
curl	curl	𝑥 ≤ 7.21.2	CNA
curl	curl	𝑥 ≤ 7.21.1	CNA
curl	curl	𝑥 ≤ 7.21.0	CNA
curl	curl	𝑥 ≤ 7.20.1	CNA
curl	curl	𝑥 ≤ 7.20.0	CNA
curl	curl	𝑥 ≤ 7.19.7	CNA
curl	curl	𝑥 ≤ 7.19.6	CNA
curl	curl	𝑥 ≤ 7.19.5	CNA
curl	curl	𝑥 ≤ 7.19.4	CNA
curl	curl	𝑥 ≤ 7.19.3	CNA
curl	curl	𝑥 ≤ 7.19.2	CNA
curl	curl	𝑥 ≤ 7.19.1	CNA
curl	curl	𝑥 ≤ 7.19.0	CNA
curl	curl	𝑥 ≤ 7.18.2	CNA
curl	curl	𝑥 ≤ 7.18.1	CNA
curl	curl	𝑥 ≤ 7.18.0	CNA
curl	curl	𝑥 ≤ 7.17.1	CNA
curl	curl	𝑥 ≤ 7.17.0	CNA
curl	curl	𝑥 ≤ 7.16.4	CNA
curl	curl	𝑥 ≤ 7.16.3	CNA
curl	curl	𝑥 ≤ 7.16.2	CNA
curl	curl	𝑥 ≤ 7.16.1	CNA
curl	curl	𝑥 ≤ 7.16.0	CNA
curl	curl	𝑥 ≤ 7.15.5	CNA
curl	curl	𝑥 ≤ 7.15.4	CNA
curl	curl	𝑥 ≤ 7.15.3	CNA
curl	curl	𝑥 ≤ 7.15.2	CNA
curl	curl	𝑥 ≤ 7.15.1	CNA
curl	curl	𝑥 ≤ 7.15.0	CNA
curl	curl	𝑥 ≤ 7.14.1	CNA

Debian Releases

Debian Product

Codename

curl

bookworm	no-dsa
bookworm (security)	vulnerable
bullseye	postponed
bullseye (security)	vulnerable
forky	8.20.0-1 fixed
sid	8.20.0-1 fixed
trixie	no-dsa

Ubuntu Releases

Ubuntu Product

Codename

curl

bionic	needed
focal	needed
jammy	Fixed 7.81.0-1ubuntu1.24 released
noble	Fixed 8.5.0-2ubuntu10.9 released
questing	Fixed 8.14.1-2ubuntu1.3 released
resolute	Fixed 8.18.0-1ubuntu2.1 released
trusty	needed
xenial	needed

openSUSE / SLES Releases

openSUSE Product

Release

curl

suse enterprise sap 15 SP4	8.14.1-150400.5.83.1 fixed
suse enterprise sap 15 SP5	8.14.1-150400.5.83.1 fixed
suse enterprise server 15 SP4	8.14.1-150400.5.83.1 fixed
suse enterprise server 15 SP5	8.14.1-150400.5.83.1 fixed

libcurl-devel

suse enterprise sap 15 SP4	8.14.1-150400.5.83.1 fixed
suse enterprise sap 15 SP5	8.14.1-150400.5.83.1 fixed
suse enterprise server 15 SP4	8.14.1-150400.5.83.1 fixed
suse enterprise server 15 SP5	8.14.1-150400.5.83.1 fixed

libcurl4

suse enterprise sap 15 SP4	8.14.1-150400.5.83.1 fixed
suse enterprise sap 15 SP5	8.14.1-150400.5.83.1 fixed
suse enterprise server 15 SP4	8.14.1-150400.5.83.1 fixed
suse enterprise server 15 SP5	8.14.1-150400.5.83.1 fixed

libcurl4-32bit

suse enterprise sap 15 SP4	8.14.1-150400.5.83.1 fixed
suse enterprise sap 15 SP5	8.14.1-150400.5.83.1 fixed
suse enterprise server 15 SP4	8.14.1-150400.5.83.1 fixed
suse enterprise server 15 SP5	8.14.1-150400.5.83.1 fixed

Vulnerability Media Exposure

[GERMAN] cURL: Mehrere Schwachstellen
Ein Angreifer kann mehrere Schwachstellen in cURL ausnutzen, um Sicherheitsvorkehrungen zu umgehen, vertrauliche Informationen offenzulegen oder Daten zu manipulieren.
Published: 2026-04-28T22:00:00+00:00

References

https://curl.se/docs/CVE-2026-6253.html

https://curl.se/docs/CVE-2026-6253.json

https://hackerone.com/reports/3669637

http://www.openwall.com/lists/oss-security/2026/04/29/11

https://hackerone.com/reports/3669637