Bug 2509787 - CVE-2026-9546 curl: libcurl: Information disclosure due to persistent Referer header [fedora-all]
Summary: CVE-2026-9546 curl: libcurl: Information disclosure due to persistent Referer...
Keywords:
Status: CLOSED ERRATA
Alias: None
Product: Fedora
Classification: Fedora
Component: curl
Version: 45
Hardware: Unspecified
OS: Unspecified
medium
medium
Target Milestone: ---
Assignee: Jan Macku
QA Contact: Fedora Extras Quality Assurance
URL:
Whiteboard: {"flaws": ["f740ab0b-53a7-444e-9797-f...
Depends On:
Blocks: CVE-2026-9546
TreeView+ depends on / blocked
 
Reported: 2026-07-31 14:40 UTC by Tomas Hoger
Modified: 2026-08-27 08:30 UTC (History)
7 users (show)

Fixed In Version: curl-8.18.0-9.fc44
Clone Of:
Environment:
Last Closed: 2026-08-27 08:30:39 UTC
Type: ---
Embargoed:


Attachments (Terms of Use)

Description Tomas Hoger 2026-07-31 14:40:45 UTC
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.

A vulnerability in libcurl caused the HTTP `Referer:` header to persist even
when explicitly cleared. While the documentation states that passing NULL to
`CURLOPT_REFERER` suppresses the header, the option failed to clear the
internal state. As a result the previous referrer string was erroneously
reused and sent in subsequent requests, potentially leaking sensitive
information to unintended servers.

Comment 1 Aoife Moloney 2026-08-17 15:44:22 UTC
This bug appears to have been reported against 'rawhide' during the Fedora Linux 45 development cycle.
Changing version to 45.

Comment 2 Fedora Update System 2026-08-25 08:52:54 UTC
FEDORA-2026-2f88b83676 (curl-8.18.0-9.fc44) has been submitted as an update to Fedora 44.
https://bodhi.fedoraproject.org/updates/FEDORA-2026-2f88b83676

Comment 3 Fedora Update System 2026-08-26 02:02:01 UTC
FEDORA-2026-2f88b83676 has been pushed to the Fedora 44 testing repository.
Soon you'll be able to install the update with the following command:
`sudo dnf upgrade --enablerepo=updates-testing --refresh --advisory=FEDORA-2026-2f88b83676`
You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2026-2f88b83676

See also https://fedoraproject.org/wiki/QA:Updates_Testing for more information on how to test updates.

Comment 4 Jan Macku 2026-08-26 14:11:13 UTC
f43 is not affected - Affected versions: curl 8.18.0 to and including 8.20.0

Comment 5 Fedora Update System 2026-08-27 00:55:37 UTC
FEDORA-2026-2f88b83676 (curl-8.18.0-9.fc44) has been pushed to the Fedora 44 stable repository.
If problem still persists, please make note of it in this bug report.


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