CVE-2025-46420 identifies a memory leak vulnerability in libsoup, specifically within the soup_header_parse_quality_list() function. Libsoup is a widely used HTTP client/server library in Linux environments, including Red Hat Enterprise Linux 8. The vulnerability arises when the function parses a quality list header containing elements composed entirely of zeroes, failing to release allocated memory after the effective lifetime of the data. This results in a gradual memory leak that can accumulate over time, potentially leading to resource exhaustion and denial of service (DoS). The CVSS 3.1 base score is 6.5, reflecting a medium severity with network attack vector (AV:N), low attack complexity (AC:L), no privileges required (PR:N), but requiring user interaction (UI:R). The impact is limited to availability (A:H) with no confidentiality or integrity loss. Exploitation does not require authentication, and the attacker can trigger the leak remotely by sending crafted HTTP headers to vulnerable services. Although no exploits are currently known in the wild, the vulnerability poses a risk to systems that process untrusted HTTP headers, especially in server or proxy roles. The lack of patches at the time of publication means organizations must monitor for updates and consider temporary mitigations. The vulnerability is specific to Red Hat Enterprise Linux 8, which is widely deployed in enterprise and government environments.

For European organizations, this vulnerability could lead to denial of service conditions on critical servers running Red Hat Enterprise Linux 8, especially those exposed to untrusted networks or the internet. Memory leaks can degrade system performance over time, causing service interruptions or crashes that impact business continuity. Industries relying on stable and secure HTTP services, such as finance, healthcare, telecommunications, and government, may experience operational disruptions. The absence of confidentiality or integrity impact reduces risks of data breaches, but availability degradation can still cause significant operational and reputational damage. Organizations with automated or high-volume HTTP traffic processing are particularly vulnerable to rapid resource exhaustion. Additionally, the requirement for user interaction implies that some form of client or intermediary processing is needed, which may limit exploitation scenarios but does not eliminate risk. The medium severity rating suggests prioritizing remediation but not immediate emergency response unless exploitation is observed.

1. Monitor Red Hat and libsoup vendor advisories closely for official patches addressing CVE-2025-46420 and apply them promptly once available. 2. Temporarily restrict or filter HTTP traffic that includes suspicious or malformed quality list headers, especially those with zero elements, using web application firewalls or network filtering tools. 3. Limit exposure of services using libsoup to trusted networks or authenticated users to reduce attack surface. 4. Implement resource monitoring and alerting on memory usage for services relying on libsoup to detect abnormal consumption early. 5. Consider deploying rate limiting or connection throttling to mitigate potential exploitation attempts that trigger memory leaks. 6. Review and update incident response plans to include detection and mitigation steps for memory leak-based denial of service attacks. 7. Engage with Red Hat support for guidance on interim workarounds if patches are delayed. 8. Conduct internal code audits or testing if custom applications use libsoup to identify and mitigate similar parsing issues.