# CVE-2026-12547: Libsoup: information disclosure in libsoup via soupauthmanager proxy credential leak on proxy switch

> Attackers can steal proxy credentials when the proxy configuration changes because libsoup fails to scope cached authentication headers to the specific proxy authority.

- **Severity:** Low 3.4 (`CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 21 Jul 2026
- **Updated:** 21 Jul 2026
- **Also known as:** AZL-93237, DEBIAN-CVE-2026-12547, ECHO-d505-ef7c-089c, GHSA-gmf9-8jmv-v2q8, OESA-2026-4388, UBUNTU-CVE-2026-12547

## What is CVE-2026-12547?

CVE-2026-12547 is a low-severity vulnerability in Red Hat Enterprise Linux 10, published on 21 Jul 2026. An attacker needs administrator access to exploit it, and only if a user opens a file or follows a link.

### Official description

SoupAuthManager caches proxy authentication credentials without scoping them to the proxy authority (host:port). When the proxy configuration changes (e.g., via system settings or WPAD), cached Proxy-Authorization headers from the previous proxy are sent to the new proxy, leaking credentials.

Weakness: CWE-201 (Insertion of Sensitive Information Into Sent Data)

## Which versions are affected by CVE-2026-12547?


## How do I fix CVE-2026-12547?

Apply the vendor's patch.

## Is CVE-2026-12547 being exploited?

There is no known exploitation of CVE-2026-12547 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-12547 and fix it if it is affected.

What it is: CVE-2026-12547 is a low-severity vulnerability in Red Hat Enterprise Linux 10, published on 21 Jul 2026. An attacker needs administrator access to exploit it, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-12547 in the wild and no public exploit code.

Affected product: Red Hat Enterprise Linux 10. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-12547/ (Markdown: https://insights.sbomify.com/CVE-2026-12547/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-12547
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-12547
- OSV: https://osv.dev/vulnerability/CVE-2026-12547

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-12547/
Summaries are generated and may contain mistakes; the official description above is the record.