Enterprise LinuxOperating system · Redhat
CVE-2026-1539
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedA flaw was found in the libsoup HTTP library that can cause proxy authentication credentials to be sent to unintended destinations. When handling HTTP redirects, libsoup removes the Authorization header but does not remove the Proxy-Authorization header if the request is redirected to a different host. As a result, sensitive proxy credentials may be leaked to third-party servers. Applications using libsoup for HTTP communication may unintentionally expose proxy authentication data.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceThe libsoup HTTP library fails to strip the Proxy-Authorization header when an HTTP request is redirected to a different host. While the library correctly removes the Authorization header during redirects, it neglects to remove the Proxy-Authorization header, causing sensitive proxy credentials to be sent to third-party destination servers.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data
Enterprise LinuxOperating system
= 6.0= 7.0= 8.0= 9.0= 10.0all versionsCVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Changed
- Confidentiality
- Low
- Integrity
- None
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify if libsoup is installedRun 'rpm -qa | grep libsoup' on RHEL systems, or check for libsoup shared library files (e.g., /usr/lib*/libsoup*.so*) on other Linux distributions. For embedded systems, inspect application dependencies.Affected if libsoup package or library binary is present on the system
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Determine the installed libsoup versionRun 'rpm -q libsoup' or 'dpkg -l libsoup' to get the exact version number. Compare against the affected version ranges (all versions of GNOME Libsoup, RHEL 6.0-10.0).Affected if Any installed version of libsoup is found, since all versions are affected according to the CVE
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Identify applications using libsoup HTTP functionalitySearch application codebases for libsoup imports (e.g., #include <libsoup/soup.h> in C, or library linking). Review web applications, API clients, or services that perform HTTP requests.Affected if Any application uses libsoup for making HTTP requests
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Check if Proxy-Authorization header is usedReview application code and configuration for proxy authentication patterns. Search for 'Proxy-Authorization' header strings, proxy credential configuration, or proxy authentication logic in the codebase.Affected if The application or service is configured to use proxy authentication that would generate a Proxy-Authorization header
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Determine if HTTP redirects to different hosts occurReview application code for redirect handling (soup_session_set_property with SOUP_SESSION Follow redirects, or manual redirect logic). Analyze logs or traffic captures for 3xx responses pointing to different hostnames.Affected if The application follows HTTP redirects and the destination can vary based on the request
A user is affected if their system has any version of libsoup installed and runs an application that uses Proxy-Authorization for proxy authentication while also following redirects that could go to different hostnames.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor dataApply the latest libsoup security patch to prevent credential leakage, or implement application-level logic to explicitly clear the Proxy-Authorization header before following redirects to different hosts.
Fix this in Enterprise Linux
Scoped from the published advisory
- Consultation3.0 h
- Implementation4.0 h
- Testing4.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,648.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-1539 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-1539 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
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