# CVE-2026-15712: GNOME libsoup heap buffer over-read in HTTP/2 GOAWAY frame parsing

Source: https://junglewise.ai/threats/cve-2026-15712-gnome-libsoup-heap-buffer-over-read-in-http-2-goaway-frame  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-07-14. Updated: 2026-07-14  
License: CC BY 4.0 with a link back

CVE-2026-15712 · Severity: medium · CVSS 5.9 · Published 2026-07-14

A security vulnerability exists in libsoup, a widely used HTTP client/server library for GNOME and Linux applications. When processing specific network signals (HTTP/2 GOAWAY frames), the library may attempt to read data beyond its allocated memory because it incorrectly assumes the data is properly terminated. This can lead to an immediate application crash, causing a denial of service, or potentially allow an attacker to view fragments of sensitive information stored in the system's memory.

Technologies: [Gnome Libsoup](https://junglewise.ai/threats/technologies/libsoup). Vendors: [Gnome](https://junglewise.ai/threats/vendors/gnome).

## Quick answers

**Is CVE-2026-15712 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-15712 being exploited in the wild.

**How severe is CVE-2026-15712?** Medium severity, with a CVSS score of 5.9, published 14 July 2026.

**Which products and versions are affected?** Gnome Libsoup 3.0 to 3.7.0.

**Is there a fix for CVE-2026-15712?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-15712 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-15712?** Check whether you run Gnome Libsoup at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

A heap buffer over-read exists in libsoup (versions 3.0 through 3.7.0) within the `on_frame_recv_callback()` function of the HTTP/2 backend (`soup-client-message-io-http2.c`). The vulnerability occurs when the library processes an HTTP/2 GOAWAY frame containing 'Additional Debug Data'. The parser passes this data to `h2_debug()` using a `%s` format string, which assumes a NUL-terminated C-string. However, the underlying `nghttp2` library allocates this buffer without a NUL terminator. An unauthenticated remote attacker can send a malformed GOAWAY frame to trigger an out-of-bounds read. This typically results in a denial of service (application crash) or potential information disclosure, though the over-read is only triggered when debug logging is enabled (e.g., `G_MESSAGES_DEBUG=libsoup-http2`).

## Affected products

- GNOME libsoup 3.0 to 3.7.0
- Red Hat Red Hat Enterprise Linux 10 affected

## Timeline

- 2026-02-13: disclosed: Initial report via YesWeHack
- 2026-07-14: advisory: CVE published and NVD record created

## References

- [https://access.redhat.com/downloads/content/package-browser/](https://access.redhat.com/downloads/content/package-browser/)
- [https://access.redhat.com/security/cve/CVE-2026-15712](https://access.redhat.com/security/cve/CVE-2026-15712)
- [https://bugzilla.redhat.com/show_bug.cgi?id=2499939](https://bugzilla.redhat.com/show_bug.cgi?id=2499939)
- [https://gitlab.gnome.org/GNOME/libsoup/-/work_items/540](https://gitlab.gnome.org/GNOME/libsoup/-/work_items/540)

## Related threats

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- [libsoup heap corruption in WebSocket message reassembly](https://junglewise.ai/threats/cve-2026-102557-a-flaw-was-found-in-libsoup-when-reassembling-fragmented)