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Vulnerability · Published Sep 29, 2026 · Assigned by redhat

CVE-2026-102555Libsoup: libsoup: heap buffer overflow via uninitialized length in data-uri base64 decoding

High 8.2

In plain English

A high-severity out-of-bounds read in Red Hat Enterprise Linux 10 from Red Hat. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 42% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)8.2High
Exploit odds (30 days)0.5%top 58.5% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

A flaw was found in libsoup. The soup_uri_decode_data_uri() function incorrectly treated base64 data-URI payloads as NUL-terminated strings when calling g_base64_decode_inplace(). If the percent-decoded payload contained embedded NUL bytes, the decoded length could remain uninitialized and be used as the size of the returned GBytes. This can lead to an out-of-bounds read or application crash when processing a crafted data URI.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
AlmaLinux:10libsoup33.6.5-3.el10_2.20ALSA-2026:83618
AlmaLinux:10libsoup3-devel3.6.5-3.el10_2.20ALSA-2026:83618
AlmaLinux:10libsoup3-doc3.6.5-3.el10_2.20ALSA-2026:83618
Debian:12libsoup2.4no fix listedDEBIAN-CVE-2026-102555
Debian:13libsoup2.4no fix listedDEBIAN-CVE-2026-102555
Debian:12libsoup3no fix listedDEBIAN-CVE-2026-102555
Debian:13libsoup3no fix listedDEBIAN-CVE-2026-102555
Ubuntu:22.04:LTSlibsoup2.42.74.2-3ubuntu0.10USN-8975-1
Ubuntu:22.04:LTSlibsoup2.42.74.2-3ubuntu0.10UBUNTU-CVE-2026-102555
Ubuntu:24.04:LTSlibsoup2.42.74.3-6ubuntu1.10USN-8975-1
Ubuntu:24.04:LTSlibsoup2.42.74.3-6ubuntu1.10UBUNTU-CVE-2026-102555
Ubuntu:26.10libsoup2.4no fix listedUBUNTU-CVE-2026-102555
Ubuntu:24.04:LTSlibsoup33.4.4-5ubuntu0.10USN-8975-1
Ubuntu:24.04:LTSlibsoup33.4.4-5ubuntu0.10UBUNTU-CVE-2026-102555
Ubuntu:26.04:LTSlibsoup33.6.6-1ubuntu0.2UBUNTU-CVE-2026-102555
Ubuntu:26.04:LTSlibsoup33.6.6-1ubuntu0.2USN-8975-1
Ubuntu:26.10libsoup33.6.6-1ubuntu3.1USN-8975-1
Ubuntu:26.10libsoup33.6.6-1ubuntu3.1UBUNTU-CVE-2026-102555

Affected products (as reported)

VendorProductVersions
Red Hat Red Hat Enterprise Linux 10 see references
Red Hat Red Hat Enterprise Linux 10.0 Extended Update Support see references
Red Hat Red Hat Enterprise Linux 6 see references
Red Hat Red Hat Enterprise Linux 7 see references
Red Hat Red Hat Enterprise Linux 8 see references
Red Hat Red Hat Enterprise Linux 9 see references

Weakness: CWE-125 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H

References