Gnome Libsoup
CVE-2026-66337
A flaw was found in libsoup. An unsigned integer underflow in the soup_filter_input_stream_read_until() function causes a heap buffer over-read when parsing multipart HTTP responses. A malicious HTTP server can exploit this by sending a crafted multipart response, potentially causing the client application to crash or disclose sensitive heap memory.
What this means for your business
- It affects Gnome Libsoup. It matters if your company, or a supplier that handles your data, runs it.
- Code showing how to exploit it has been published, but real attacks have not been confirmed.
- An attacker can use it remotely, over a network, without a login, and without anyone at your company clicking anything.
- FIRST's prediction model gives it a 0.2% chance of attack attempts being seen in the next 30 days, ranking above 13% of all known flaws.
What to do
- 1Check whether your company or your suppliers run Gnome Libsoup, and which version. The affected versions are listed further down this page.
- 2If you do, apply the vendor's fix. A patch or vendor advisory has been published.
Fastnexa security experts
Not sure if your company is exposed to CVE-2026-66337?
Tell us where you run Gnome Libsoup and a Fastnexa penetration tester will check whether this flaw, or others like it, can be used against your websites, apps and network.
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Scoring
- CVSS
- 6.5 (v3.1)
- Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L- Weakness
- CWE-125
- Assigned by
- secalert@redhat.com
Dates
- Published
- 2026-07-24
- Last modified
- 2026-08-24
- Sources
- NVD
Affected products
- Gnome Libsoupall versions
- Redhat Enterprise Linux6.0, 7.0, 8.0, 9.0, 10.0
As listed in the NVD configuration data. Not a statement about your estate.