CVE-2025-12183 is a vulnerability classified under CWE-125 (Out-of-bounds Read) affecting the lz4-java library versions 1.8.0 and earlier. The issue arises from improper bounds checking during decompression of LZ4 compressed data, allowing attackers to craft malicious compressed input that triggers out-of-bounds memory reads. This can lead to two primary impacts: denial of service (DoS) by crashing the application due to invalid memory access, and unauthorized disclosure of adjacent memory contents, potentially leaking sensitive information. The vulnerability is remotely exploitable without any authentication or user interaction, as it only requires the attacker to send specially crafted compressed data to a service or application using the vulnerable library. The CVSS v4.0 score of 8.8 reflects the high impact on confidentiality and availability, with low attack complexity and no privileges required. Although no exploits have been observed in the wild yet, the widespread use of lz4-java in Java applications for compression tasks makes this a significant threat. The lack of an official patch at the time of publication necessitates interim mitigations such as input validation, limiting exposure of vulnerable components, and monitoring for anomalous decompression failures.

For European organizations, the vulnerability poses a serious risk to applications and services that utilize the lz4-java library for data compression and decompression, particularly those exposed to untrusted input such as web services, APIs, or data ingestion pipelines. Exploitation could result in service outages due to crashes, impacting availability and potentially causing operational disruptions. Additionally, the out-of-bounds read could expose sensitive memory contents, leading to confidentiality breaches. This is especially critical for sectors handling sensitive personal data or intellectual property, such as finance, healthcare, and government. The remote and unauthenticated nature of the exploit increases the attack surface, making it easier for threat actors to target vulnerable systems. The absence of known exploits currently provides a window for proactive mitigation, but the high CVSS score indicates that exploitation could have severe consequences if weaponized.

1. Immediately inventory all software components and applications using lz4-java version 1.8.0 or earlier. 2. Monitor vendor announcements and apply official patches or updates as soon as they become available. 3. If patches are not yet released, implement strict input validation to reject malformed or suspicious compressed data before decompression. 4. Employ sandboxing or containerization techniques to isolate decompression processes, limiting the impact of potential crashes or memory disclosures. 5. Use runtime application self-protection (RASP) or intrusion detection systems to detect anomalous decompression failures or memory access violations. 6. Restrict network exposure of services that perform decompression of untrusted data, applying network segmentation and firewall rules. 7. Conduct code reviews and static analysis to identify other potential unsafe memory operations in compression-related code. 8. Educate developers and security teams about the risks of processing untrusted compressed input and best secure coding practices.