CVE catalog

CVE-2026-6253

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 differe

[CVE catalog]

Severity: Medium · CVSS 5.9CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
Published: Apr 28, 2026, 10:00:00 PM UTC
Source: [NVD] · [CVE record]
EPSS: 0.72% · Oct 25, 2026

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

Vulnerable and fixed packages

Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.

Distribution	Package	Release	Version	Status
Debian	curl	sid	`8.23.0-1`	fixed
Debian	curl	forky	`8.22.0-1`	fixed
Debian	curl	trixie	`8.14.1-2+deb13u5`	fixed
Debian	curl	trixie-security	`8.14.1-2+deb13u7`	fixed
Debian	curl	bookworm	`7.88.1-10+deb12u15`	vulnerable
Debian	curl	bookworm-security	`7.88.1-10+deb12u5`	vulnerable
Cpe	curl	Not reported	`8.5.0-2ubuntu10.9`	fixed
Cpe	libcurl3t64-gnutls	Not reported	`8.5.0-2ubuntu10.9`	fixed
Cpe	libcurl4-doc	Not reported	`8.5.0-2ubuntu10.9`	fixed
Cpe	libcurl4-gnutls-dev	Not reported	`8.5.0-2ubuntu10.9`	fixed
Cpe	libcurl4-openssl-dev	Not reported	`8.5.0-2ubuntu10.9`	fixed
Cpe	libcurl4t64	Not reported	`8.5.0-2ubuntu10.9`	fixed
Cpe	curl	Not reported	Not reported	vulnerable
Cpe	curl	Not reported	`8.20.0`	fixed
Cpe	curl	Not reported	`8.20.0`	fixed
Alpine	curl	3.21	`8.14.1-r3`	fixed
Alpine	curl	3.22	`8.14.1-r4`	fixed
Alpine	curl	3.23	`8.20.0-r0`	fixed
Alpine	curl	3.24	`8.20.0-r0`	fixed

Fixed-version evidence

Distribution	Package	Type	Release	Fixed version	Urgency	Origin	Bugs
Debian	curl	source	sid	`8.20.0~rc3-1`	not yet assigned	Not reported	Not reported
Debian	curl	source	forky	`8.20.0~rc3-1`	not yet assigned	Not reported	Not reported
Debian	curl	source	trixie	`8.14.1-2+deb13u4`	not yet assigned	Not reported	Not reported
Debian	curl	source	bookworm	`(unfixed)`	not yet assigned	Not reported	Not reported
Cpe	curl	cpe	Not reported	`8.5.0-2ubuntu10.9`	Not reported	Not reported	Not reported
Cpe	libcurl3t64-gnutls	cpe	Not reported	`8.5.0-2ubuntu10.9`	Not reported	Not reported	Not reported
Cpe	libcurl4-doc	cpe	Not reported	`8.5.0-2ubuntu10.9`	Not reported	Not reported	Not reported
Cpe	libcurl4-gnutls-dev	cpe	Not reported	`8.5.0-2ubuntu10.9`	Not reported	Not reported	Not reported
Cpe	libcurl4-openssl-dev	cpe	Not reported	`8.5.0-2ubuntu10.9`	Not reported	Not reported	Not reported
Cpe	libcurl4t64	cpe	Not reported	`8.5.0-2ubuntu10.9`	Not reported	Not reported	Not reported
Cpe	curl	cpe	Not reported	`8.20.0`	Not reported	Not reported	Not reported
Cpe	curl	cpe	Not reported	`8.20.0`	Not reported	NVD-CVE-2026-6253	Not reported
Alpine	curl	apk	3.21	`8.14.1-r3`	Not reported	ALPINE-CVE-2026-6253	Not reported
Alpine	curl	apk	3.22	`8.14.1-r4`	Not reported	ALPINE-CVE-2026-6253	Not reported
Alpine	curl	apk	3.23	`8.20.0-r0`	Not reported	ALPINE-CVE-2026-6253	Not reported
Alpine	curl	apk	3.24	`8.20.0-r0`	Not reported	ALPINE-CVE-2026-6253	Not reported

Notes

[bookworm] curl: Minor issue

OpenFactory catalog packages

[Debian 12 (Bookworm)]

[curl]Affected
Details (6)
- 7.88.1-10+deb12u15 · amd64 · bookworm
  Affected
  nvd · curl · debian · bookworm; nvd · curl · debian · 12
- 7.88.1-10+deb12u15 · arm64 · bookworm
  Affected
  nvd · curl · debian · bookworm; nvd · curl · debian · 12
- 8.14.1-2+deb13u2~bpo13+1 · amd64 · bookworm-backports
  Affected
  nvd · curl · debian · bookworm; nvd · curl · debian · 12
- 8.14.1-2+deb13u2~bpo13+1 · arm64 · bookworm-backports
  Affected
  nvd · curl · debian · bookworm; nvd · curl · debian · 12
- 7.88.1-10+deb12u5 · amd64 · bookworm-security
  Affected
  nvd · curl · debian · bookworm; nvd · curl · debian · 12
- 7.88.1-10+deb12u5 · arm64 · bookworm-security
  Affected
  nvd · curl · debian · bookworm; nvd · curl · debian · 12
[libcurl3-gnutls]Affected
Source package: [curl]
Details (6)
- 7.88.1-10+deb12u15 · amd64 · bookworm
  Affected
  nvd · curl · debian · bookworm; nvd · curl · debian · 12
- 7.88.1-10+deb12u15 · arm64 · bookworm
  Affected
  nvd · curl · debian · bookworm; nvd · curl · debian · 12
- 8.14.1-2+deb13u2~bpo13+1 · amd64 · bookworm-backports
  Affected
  nvd · curl · debian · bookworm; nvd · curl · debian · 12
- 8.14.1-2+deb13u2~bpo13+1 · arm64 · bookworm-backports
  Affected
  nvd · curl · debian · bookworm; nvd · curl · debian · 12
- 7.88.1-10+deb12u5 · amd64 · bookworm-security
  Affected
  nvd · curl · debian · bookworm; nvd · curl · debian · 12
- 7.88.1-10+deb12u5 · arm64 · bookworm-security
  Affected
  nvd · curl · debian · bookworm; nvd · curl · debian · 12
[libcurl3-nss]Affected
Source package: [curl]
Details (4)
- 7.88.1-10+deb12u15 · amd64 · bookworm
  Affected
  nvd · curl · debian · bookworm; nvd · curl · debian · 12
- 7.88.1-10+deb12u15 · arm64 · bookworm
  Affected
  nvd · curl · debian · bookworm; nvd · curl · debian · 12
- 7.88.1-10+deb12u5 · amd64 · bookworm-security
  Affected
  nvd · curl · debian · bookworm; nvd · curl · debian · 12
- 7.88.1-10+deb12u5 · arm64 · bookworm-security
  Affected
  nvd · curl · debian · bookworm; nvd · curl · debian · 12
[libcurl4]Affected
Source package: [curl]
Details (6)
- 7.88.1-10+deb12u15 · amd64 · bookworm
  Affected
  nvd · curl · debian · bookworm; nvd · curl · debian · 12
- 7.88.1-10+deb12u15 · arm64 · bookworm
  Affected
  nvd · curl · debian · bookworm; nvd · curl · debian · 12
- 8.14.1-2+deb13u2~bpo13+1 · amd64 · bookworm-backports
  Affected
  nvd · curl · debian · bookworm; nvd · curl · debian · 12
- 8.14.1-2+deb13u2~bpo13+1 · arm64 · bookworm-backports
  Affected
  nvd · curl · debian · bookworm; nvd · curl · debian · 12
- 7.88.1-10+deb12u5 · amd64 · bookworm-security
  Affected
  nvd · curl · debian · bookworm; nvd · curl · debian · 12
- 7.88.1-10+deb12u5 · arm64 · bookworm-security
  Affected
  nvd · curl · debian · bookworm; nvd · curl · debian · 12
[libcurl4-doc]Affected
Source package: [curl]
Details (6)
- 7.88.1-10+deb12u15 · all · bookworm
  Affected
  nvd · curl · debian · bookworm; nvd · curl · debian · 12
- 7.88.1-10+deb12u15 · all · bookworm
  Affected
  nvd · curl · debian · bookworm; nvd · curl · debian · 12
- 8.14.1-2+deb13u2~bpo13+1 · all · bookworm-backports
  Affected
  nvd · curl · debian · bookworm; nvd · curl · debian · 12
- 8.14.1-2+deb13u2~bpo13+1 · all · bookworm-backports
  Affected
  nvd · curl · debian · bookworm; nvd · curl · debian · 12
- 7.88.1-10+deb12u5 · all · bookworm-security
  Affected
  nvd · curl · debian · bookworm; nvd · curl · debian · 12
- 7.88.1-10+deb12u5 · all · bookworm-security
  Affected
  nvd · curl · debian · bookworm; nvd · curl · debian · 12
[libcurl4-gnutls-dev]Affected
Source package: [curl]
Details (6)
- 7.88.1-10+deb12u15 · amd64 · bookworm
  Affected
  nvd · curl · debian · bookworm; nvd · curl · debian · 12
- 7.88.1-10+deb12u15 · arm64 · bookworm
  Affected
  nvd · curl · debian · bookworm; nvd · curl · debian · 12
- 8.14.1-2+deb13u2~bpo13+1 · amd64 · bookworm-backports
  Affected
  nvd · curl · debian · bookworm; nvd · curl · debian · 12
- 8.14.1-2+deb13u2~bpo13+1 · arm64 · bookworm-backports
  Affected
  nvd · curl · debian · bookworm; nvd · curl · debian · 12
- 7.88.1-10+deb12u5 · amd64 · bookworm-security
  Affected
  nvd · curl · debian · bookworm; nvd · curl · debian · 12
- 7.88.1-10+deb12u5 · arm64 · bookworm-security
  Affected
  nvd · curl · debian · bookworm; nvd · curl · debian · 12
[libcurl4-nss-dev]Affected
Source package: [curl]
Details (4)
- 7.88.1-10+deb12u15 · amd64 · bookworm
  Affected
  nvd · curl · debian · bookworm; nvd · curl · debian · 12
- 7.88.1-10+deb12u15 · arm64 · bookworm
  Affected
  nvd · curl · debian · bookworm; nvd · curl · debian · 12
- 7.88.1-10+deb12u5 · amd64 · bookworm-security
  Affected
  nvd · curl · debian · bookworm; nvd · curl · debian · 12
- 7.88.1-10+deb12u5 · arm64 · bookworm-security
  Affected
  nvd · curl · debian · bookworm; nvd · curl · debian · 12
[libcurl4-openssl-dev]Affected
Source package: [curl]
Details (6)
- 7.88.1-10+deb12u15 · amd64 · bookworm
  Affected
  nvd · curl · debian · bookworm; nvd · curl · debian · 12
- 7.88.1-10+deb12u15 · arm64 · bookworm
  Affected
  nvd · curl · debian · bookworm; nvd · curl · debian · 12
- 8.14.1-2+deb13u2~bpo13+1 · amd64 · bookworm-backports
  Affected
  nvd · curl · debian · bookworm; nvd · curl · debian · 12
- 8.14.1-2+deb13u2~bpo13+1 · arm64 · bookworm-backports
  Affected
  nvd · curl · debian · bookworm; nvd · curl · debian · 12
- 7.88.1-10+deb12u5 · amd64 · bookworm-security
  Affected
  nvd · curl · debian · bookworm; nvd · curl · debian · 12
- 7.88.1-10+deb12u5 · arm64 · bookworm-security
  Affected
  nvd · curl · debian · bookworm; nvd · curl · debian · 12

[Debian 13 (Trixie)]

[curl]Fixed
Details (5)
- 8.14.1-2+deb13u4 · amd64 · trixie
  Fixed · Fixed: 8.14.1-2+deb13u4
  nvd · curl · debian · 13
- 8.14.1-2+deb13u4 · arm64 · trixie
  Fixed · Fixed: 8.14.1-2+deb13u4
  nvd · curl · debian · 13
- 8.21.0-2~bpo13+1 · amd64 · trixie-backports
  Fixed · Fixed: 8.14.1-2+deb13u4
  nvd · curl · debian · 13
- 8.21.0-2~bpo13+1 · arm64 · trixie-backports
  Fixed · Fixed: 8.14.1-2+deb13u4
  nvd · curl · debian · 13
- 8.14.1-2+deb13u7 · amd64 · trixie-security
  Fixed · Fixed: 8.14.1-2+deb13u4
  nvd · curl · debian · 13
[libcurl3t64-gnutls]Fixed
Source package: [curl]
Details (5)
- 8.14.1-2+deb13u4 · amd64 · trixie
  Fixed · Fixed: 8.14.1-2+deb13u4
  nvd · curl · debian · 13
- 8.14.1-2+deb13u4 · arm64 · trixie
  Fixed · Fixed: 8.14.1-2+deb13u4
  nvd · curl · debian · 13
- 8.21.0-2~bpo13+1 · amd64 · trixie-backports
  Fixed · Fixed: 8.14.1-2+deb13u4
  nvd · curl · debian · 13
- 8.21.0-2~bpo13+1 · arm64 · trixie-backports
  Fixed · Fixed: 8.14.1-2+deb13u4
  nvd · curl · debian · 13
- 8.14.1-2+deb13u7 · amd64 · trixie-security
  Fixed · Fixed: 8.14.1-2+deb13u4
  nvd · curl · debian · 13
[libcurl4-doc]Fixed
Source package: [curl]
Details (5)
- 8.14.1-2+deb13u4 · all · trixie
  Fixed · Fixed: 8.14.1-2+deb13u4
  nvd · curl · debian · 13
- 8.14.1-2+deb13u4 · all · trixie
  Fixed · Fixed: 8.14.1-2+deb13u4
  nvd · curl · debian · 13
- 8.21.0-2~bpo13+1 · all · trixie-backports
  Fixed · Fixed: 8.14.1-2+deb13u4
  nvd · curl · debian · 13
- 8.21.0-2~bpo13+1 · all · trixie-backports
  Fixed · Fixed: 8.14.1-2+deb13u4
  nvd · curl · debian · 13
- 8.14.1-2+deb13u7 · all · trixie-security
  Fixed · Fixed: 8.14.1-2+deb13u4
  nvd · curl · debian · 13
[libcurl4-gnutls]Fixed
Source package: [curl]
Details (2)
- 8.21.0-2~bpo13+1 · amd64 · trixie-backports
  Fixed · Fixed: 8.14.1-2+deb13u4
  nvd · curl · debian · 13
- 8.21.0-2~bpo13+1 · arm64 · trixie-backports
  Fixed · Fixed: 8.14.1-2+deb13u4
  nvd · curl · debian · 13
[libcurl4-gnutls-dev]Fixed
Source package: [curl]
Details (5)
- 8.14.1-2+deb13u4 · amd64 · trixie
  Fixed · Fixed: 8.14.1-2+deb13u4
  nvd · curl · debian · 13
- 8.14.1-2+deb13u4 · arm64 · trixie
  Fixed · Fixed: 8.14.1-2+deb13u4
  nvd · curl · debian · 13
- 8.21.0-2~bpo13+1 · amd64 · trixie-backports
  Fixed · Fixed: 8.14.1-2+deb13u4
  nvd · curl · debian · 13
- 8.21.0-2~bpo13+1 · arm64 · trixie-backports
  Fixed · Fixed: 8.14.1-2+deb13u4
  nvd · curl · debian · 13
- 8.14.1-2+deb13u7 · amd64 · trixie-security
  Fixed · Fixed: 8.14.1-2+deb13u4
  nvd · curl · debian · 13
[libcurl4-openssl-dev]Fixed
Source package: [curl]
Details (5)
- 8.14.1-2+deb13u4 · amd64 · trixie
  Fixed · Fixed: 8.14.1-2+deb13u4
  nvd · curl · debian · 13
- 8.14.1-2+deb13u4 · arm64 · trixie
  Fixed · Fixed: 8.14.1-2+deb13u4
  nvd · curl · debian · 13
- 8.21.0-2~bpo13+1 · amd64 · trixie-backports
  Fixed · Fixed: 8.14.1-2+deb13u4
  nvd · curl · debian · 13
- 8.21.0-2~bpo13+1 · arm64 · trixie-backports
  Fixed · Fixed: 8.14.1-2+deb13u4
  nvd · curl · debian · 13
- 8.14.1-2+deb13u7 · amd64 · trixie-security
  Fixed · Fixed: 8.14.1-2+deb13u4
  nvd · curl · debian · 13
[libcurl4t64]Fixed
Source package: [curl]
Details (5)
- 8.14.1-2+deb13u4 · amd64 · trixie
  Fixed · Fixed: 8.14.1-2+deb13u4
  nvd · curl · debian · 13
- 8.14.1-2+deb13u4 · arm64 · trixie
  Fixed · Fixed: 8.14.1-2+deb13u4
  nvd · curl · debian · 13
- 8.21.0-2~bpo13+1 · amd64 · trixie-backports
  Fixed · Fixed: 8.14.1-2+deb13u4
  nvd · curl · debian · 13
- 8.21.0-2~bpo13+1 · arm64 · trixie-backports
  Fixed · Fixed: 8.14.1-2+deb13u4
  nvd · curl · debian · 13
- 8.14.1-2+deb13u7 · amd64 · trixie-security
  Fixed · Fixed: 8.14.1-2+deb13u4
  nvd · curl · debian · 13

Observed: Oct 27, 2026, 7:54:59 AM UTC

References

[CERT-Bund public advisories] · [Debian Security Tracker] · [FIRST EPSS] · [National Vulnerability Database (NVD)] · [OSV Package Vulnerability Database] · [Red Hat security advisories and VEX] · [SUSE security advisories and VEX] · [Ubuntu Security Notices (USN)]