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

High 8.2 Published 29 Sep 2026 Updated 15 Oct 2026

Attackers can cause application crashes or out-of-bounds reads in libsoup by sending crafted data URIs with embedded NUL bytes.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: Not needed
Fix: Available

What is CVE-2026-102555?

CVE-2026-102555 is a high-severity memory corruption vulnerability in Redhat Enterprise Linux, published on 29 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

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.

Weakness: CWE-125

Which versions are affected by CVE-2026-102555?

It affects 2 products.

Products include Gnome Libsoup, Redhat Enterprise Linux.

How do I fix CVE-2026-102555?

Apply the vendor's patch.

Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.

Is CVE-2026-102555 being exploited?

There is no known exploitation of CVE-2026-102555 in the wild and no public exploit code.

All Redhat Enterprise Linux vulnerabilities

Sources

Also known as AZL-105552, DEBIAN-CVE-2026-102555, ECHO-940b-9dd5-9d88, GHSA-vfxx-hcqj-vrh4, ROOT-OS-DEBIAN-13-CVE-2026-102555, UBUNTU-CVE-2026-102555.