Quick answers
- Is CVE-2026-102558 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-102558 being exploited in the wild.
- How severe is CVE-2026-102558?
- High severity, with a CVSS score of 8.6, published 29 September 2026.
- Which products and versions are affected?
- GNOME libsoup.
- Is there a fix for CVE-2026-102558?
- 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-2026-102558 attacked?
- It is attacked over the network.
- Am I affected by CVE-2026-102558?
- Check whether you run Gnome Libsoup. 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
The vulnerability exists in SoupWebsocketConnection when max-incoming-payload-size is set to 0 (unlimited). An attacker-controlled WebSocket frame length can cause the incoming GByteArray to grow until integer wrapping occurs, resulting in a heap buffer overflow during frame data reading. This requires network access to a WebSocket endpoint and affects both memory safety and availability; the attack is unauthenticated and requires no user interaction.
Affected products
- GNOME libsoup
Timeline
- 2026-09-29: disclosed