CVE-2025-13601 is a heap-based buffer overflow vulnerability identified in the glib library, specifically within the g_escape_uri_string() function. This function is responsible for escaping URI strings by replacing unacceptable characters with their percent-encoded equivalents. The vulnerability occurs due to an integer overflow or wraparound during the calculation of the buffer size needed to store the escaped string. When the input string contains a very large number of characters that require escaping, the length calculation can overflow, resulting in an underestimation of the buffer size. Consequently, the function allocates a buffer smaller than necessary and writes beyond its boundary when performing the escape operation. This out-of-bounds write can corrupt adjacent memory on the heap, potentially leading to arbitrary code execution, application crashes, or other integrity and availability issues. The vulnerability does not require any privileges or user interaction to exploit, but the attacker must be able to supply crafted input to the vulnerable function. The CVSS v3.1 base score is 7.7 (high), reflecting the local attack vector, low attack complexity, no privileges required, no user interaction, and high impact on integrity and availability. The affected product is Red Hat Enterprise Linux 10, which includes the vulnerable glib version. No public exploits or proof-of-concept code are currently known. The issue was published on November 26, 2025, and is assigned CVE-2025-13601. The root cause is a classic integer overflow leading to heap buffer overflow, a common and dangerous class of vulnerabilities in C-based libraries handling untrusted input.

For European organizations, this vulnerability poses a significant risk, especially for those running Red Hat Enterprise Linux 10 or other Linux distributions using the affected glib version. Systems processing untrusted URI inputs—such as web servers, proxy servers, or applications handling network requests—are particularly vulnerable. Exploitation could allow attackers to corrupt memory, potentially leading to arbitrary code execution, denial of service, or system instability. This could compromise the integrity and availability of critical services, impacting business operations and data security. Given the lack of required privileges or user interaction, attackers with local access or the ability to send crafted inputs remotely (if the vulnerable function is exposed) could exploit this flaw. The absence of known exploits in the wild currently reduces immediate risk but does not eliminate the threat, as attackers may develop exploits post-disclosure. European sectors such as finance, government, telecommunications, and critical infrastructure that rely heavily on Red Hat Enterprise Linux are at higher risk. The vulnerability could also be leveraged in supply chain attacks or lateral movement within compromised networks.

Organizations should prioritize applying official patches from Red Hat as soon as they become available to address CVE-2025-13601. Until patches are deployed, administrators should audit applications and services that utilize the g_escape_uri_string() function, especially those exposed to untrusted input, and consider implementing input validation or filtering to limit the number of escapable characters in URI inputs. Employing memory protection mechanisms such as Address Space Layout Randomization (ASLR), stack canaries, and heap protection can help mitigate exploitation impact. Monitoring logs for abnormal crashes or suspicious input patterns targeting URI processing functions can aid early detection. Network segmentation and limiting local access can reduce the attack surface. Additionally, organizations should review their incident response plans to prepare for potential exploitation scenarios. Coordination with Red Hat support and subscribing to security advisories will ensure timely updates and information.