8.6

CVE-2026-102559: gnome libsoup Out-of-bounds Read

CVSS: 8.6v3.1HighModified
AliasesUBUNTU-CVE-2026-102559DEBIAN-CVE-2026-102559
Published 29-09-2026Last modified 19-10-2026
Open JSON

Vulnerability summary

CVE-2026-102559 is a high (CVSS 8.6) Out-of-bounds Read vulnerability in gnome libsoup. EPSS estimates a 0.40% chance of exploitation in the next 30 days, higher than 33.1% of scored vulnerabilities.

Overall risk
34/100
0100
Medium · default modelHow is this calculated?
CVSS score
8.6/10
010
High · v3.1 (CVE.org)
EPSS score
0.40%
0%100%
Low · Change unavailable
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 8 · Related 5
OPENSUSE-SU-2026:12084-1RHSA-2026:83384RHSA-2026:83618RHSA-2026:84586SUSE-SU-2026:4616-1SUSE-SU-2026:4631-1

Timeline

  1. 29-09-2026
    PublishedVulnerability first disclosed.
  2. 19-10-2026
    Last modifiedVulnerability information updated.

Description

A flaw was found in libsoup. When constructing a masked WebSocket client frame for a very large outgoing payload, size values passed to GByteArray allocation APIs could be truncated while the masking routine still used the full length, causing a heap buffer overflow.

CVSS metrics

4 scores · 4 sources · 1 version

EPSS trend

Probability

0.40%

Chance of exploitation in the next 30 days

Percentile

33%

Versus all other CVEs

30-day change

Change unavailable

Change unavailable

30-09-202619-10-2026
EPSS score
0.40%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected 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
Redhat1 product

4 vendors · 6 products

References

9 links