Bug 2528508

Summary: CVE-2026-85197 libsoup3: libsoup: Heap use-after-free in libsoup HTTP/2 client on_data_read() via GOAWAY during body upload [fedora-all]
Product: [Fedora] Fedora Reporter: Vladimir Vasilev <vvasilev>
Component: libsoup3Assignee: Gwyn Ciesla <gwync>
Status: NEW --- QA Contact:
Severity: high Docs Contact:
Priority: high    
Version: rawhideCC: gnome-sig, gwync, mcrha
Target Milestone: ---Keywords: Security, SecurityTracking
Target Release: ---   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard: {"flaws": ["dd915ac2-42e6-400f-b632-c4fbf001c378"]}
Fixed In Version: Doc Type: ---
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
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Bug Depends On:    
Bug Blocks: 2528425    

Description Vladimir Vasilev 2026-09-04 14:24:28 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 heap use-after-free vulnerability exists in libsoup's HTTP/2 client implementation. When a GNOME application sends an HTTP/2 POST request with a file body (using a non-pollable GInputStream such as GFileInputStream), the body data is read asynchronously via g_input_stream_read_async(). If the remote HTTP/2 server sends a GOAWAY frame while this async read is pending, the SoupHTTP2MessageDatastructure is freed through the shutdown path, but the async read callback on_data_read() still fires afterward, accessing the freed heap memory.

This is a remotely-triggerable heap use-after-free — a malicious HTTP/2 server (or MITM attacker) can deterministically trigger it when any GNOME application uploads a file over HTTPS with HTTP/2. Affected applications include GNOME Web (Epiphany), GNOME Software, Flatpak, and any GLib-based application using SoupSession for HTTP/2 file uploads.

Impact type: Heap use-after-free (CWE-416) — the freed 168-byte SoupHTTP2MessageData struct is read after free, and the freed data_source_buffer may also be written to by the still-pending async I/O operation. This constitutes memory corruption with potential for information disclosure or code execution.