CVE-2026-66337: gnome libsoup Out-of-bounds Read
Vulnerability summary
CVE-2026-66337 is a medium (CVSS 6.5) Out-of-bounds Read vulnerability in gnome libsoup. EPSS estimates a 0.25% chance of exploitation in the next 30 days, higher than 14.8% of scored vulnerabilities. 1 public exploit is recorded.
Timeline
- 24-07-2026PublishedVulnerability first disclosed.
- 27-07-2026Last modifiedVulnerability information updated.
Description
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.
CVSS metrics
4 scores · 4 sources · 1 version- OSV · UbuntuEcosystem advisory · calculated6.5MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L
- OSV · DebianEcosystem advisory · calculated6.5MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L
- NVDNIST6.5MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L
EPSS trend
Probability
0.25%
Chance of exploitation in the next 30 days
Percentile
15%
Versus all other CVEs
30-day change
+0.02 pp
From 0.23% on 19-09-2026
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
1 foundExploit Reference (bugzilla.redhat.com)
Maturity: unknown
Weaknesses
CWE · root causeAffected systems
Debian2 products
- libsoup2.4All versions (No fix recorded)
- libsoup3All versions (No fix recorded) | < 3.8.0-1
Ubuntu2 products
- libsoup2.4All versions (No fix recorded)
- libsoup3All versions (No fix recorded)
Gnome1 product
- libsoupna
Redhat1 product
- enterprise_linuxEOL6.0 | 7.0 | 8.0 | 9.0 | 10.0
4 vendors · 6 products
References
7 links- bugzilla.redhat.com/show_bug.cgi?id=2506949Issue TrackingX Refsource REDHATREPORTExploitVendor Advisory
