CVE-2025-66566
highpriority · track · 0EPSS 0.006 · 49 %ileDEEUFRNLRUUSEPSS · scored 2026-10-27
yawkat LZ4 Java provides LZ4 compression for Java. Insufficient clearing of the output buffer in Java-based decompressor implementations in lz4-java 1.10.0 and earlier allows remote attackers to read previous buffer contents via crafted compressed input. In applications where the output buffer is reused without being cleared, this may lead to disclosure of sensitive data. JNI-based implementations are not affected. This vulnerability is fixed in 1.10.1.
remediations
Vendor fix, mitigation, or workaround guidance, as published by each source.
A vendor fix is available.
- Fixedjmc-0:8.2.0-18.el9_6.2.x86_64 as component of SUSE Liberty Linux 9.6 EMSsuse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
- Fixedjmc-0:8.2.0-18.el9_7.2.x86_64 as component of SUSE Liberty Linux 9suse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
cvss
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 4.6–8.2
ssvc
A stakeholder decision — act, attend, or track — from exploitation and impact.
weaknesses
The CWE weakness classes this flaw belongs to.
affected products (112)
Products and version ranges known to be affected.
advisories (13)
Vendor and ecosystem advisories describing this.
- NCSC-2026-0021Kwetsbaarheden verholpen in Oracle Database Server productenNL2026-01-21csaf · ncsc_nlNL
Oracle heeft kwetsbaarheden verholpen in Oracle Database Server producten.
- RHSA-2026:0751security update for jmc2026-01-19csaf · suse_csafDE
security update for jmc
- RHSA-2026:0752security update for jmc2026-01-19csaf · suse_csafDE
security update for jmc
- WID-SEC-W-2026-0019Red Hat Enterprise Linux (Quarkus): Mehrere SchwachstellenDeutsch2026-01-06csaf · cert_bundDE
Ein entfernter, authentisierter oder anonymer Angreifer kann mehrere Schwachstellen in Red Hat Enterprise Linux ausnutzen, um einen Cross-Site Scripting Angriff durchzuführen, einen Denial-of-Service-Zustand zu verursachen oder vertrauliche Informationen offenzulegen.
- WID-SEC-W-2026-0099Elasticsearch: Schwachstelle ermöglicht Offenlegung von InformationenDeutsch2026-01-13csaf · cert_bundDE
Ein entfernter, anonymer Angreifer kann eine Schwachstelle in Elasticsearch ausnutzen, um Informationen offenzulegen.
- WID-SEC-W-2026-0800LogStash: Schwachstelle ermöglicht Offenlegung von InformationenDeutsch2026-03-19csaf · cert_bundDE
Ein entfernter, anonymer Angreifer kann eine Schwachstelle in LogStash ausnutzen, um Informationen offenzulegen.
- WID-SEC-W-2026-1194Oracle Communications: Mehrere SchwachstellenDeutsch2026-04-21csaf · cert_bundDE
Ein entfernter, anonymer oder authentisierter Angreifer kann mehrere Schwachstellen in Oracle Communications ausnutzen, um die Vertraulichkeit, Integrität und Verfügbarkeit zu gefährden.
- WID-SEC-W-2026-1202Oracle Hyperion: Mehrere SchwachstellenDeutsch2026-04-21csaf · cert_bundDE
Ein entfernter, anonymer oder authentisierter Angreifer kann mehrere Schwachstellen in Oracle Hyperion ausnutzen, um die Vertraulichkeit, Integrität und Verfügbarkeit zu gefährden.
- WID-SEC-W-2026-1204Oracle Financial Services Applications: Mehrere SchwachstellenDeutsch2026-04-21csaf · cert_bundDE
Ein entfernter, anonymer oder authentisierter Angreifer kann mehrere Schwachstellen in Oracle Financial Services Applications ausnutzen, um die Vertraulichkeit, Integrität und Verfügbarkeit zu gefährden.
- WID-SEC-W-2026-1752IBM Business Automation Workflow: Mehrere SchwachstellenDeutsch2026-05-31csaf · cert_bundDE
Ein Angreifer kann mehrere Schwachstellen in IBM Business Automation Workflow ausnutzen, um Sicherheitsvorkehrungen zu umgehen, um einen Denial of Service Angriff durchzuführen, um Informationen offenzulegen, um Dateien zu manipulieren, und um einen Cross-Site Scripting Angriff durchzuführen.
- WID-SEC-W-2026-2431Oracle SQL Developer: Mehrere SchwachstellenDeutsch2026-07-21csaf · cert_bundDE
Ein entfernter, anonymer Angreifer kann mehrere Schwachstellen in Oracle SQL Developer ausnutzen, um die Vertraulichkeit, Integrität und Verfügbarkeit zu gefährden.
- GHSA-cmp6-m4wj-q63qyawkat LZ4 Java has a possible information leak in Java safe decompressor2025-12-05ghsa · osvUS
### Summary Insufficient clearing of the output buffer in Java-based decompressor implementations in lz4-java 1.10.0 and earlier allows remote attackers to read previous buffer contents via crafted compressed input. In applications where the output buffer is reused without being cleared, this may lead to disclosure of sensitive data. JNI-based implementations are *not* affected. ### Details During the decompression process, the lz4 algorithm may have to repeat data that was previously decompressed in the same input frame. In the Java implementation, this is implemented by copy operations within the output buffer. With a crafted input, an attacker may induce the Java implementation to copy from a region in the output buffer that does not contain decompressed data yet. If that region contains sensitive information because the output buffer was not cleared prior to decompression, that data will then be copied to the decompressed output. - `LZ4Factory.nativeInstance().safeDecompressor()` *is not* affected. - `LZ4Factory.nativeInstance().fastDecompressor()` *is* affected because it actually uses `safeInstance()` since 1.8.1. In 1.8.0 and earlier versions, this implementation is instead vulnerable to the more severe [CVE‐2025‐12183](https://sites.google.com/sonatype.com/vulnerabilities/cve-2025-12183), so downgrading is not a solution. - Both decompressors of `LZ4Factory.safeInstance()`, `LZ4Factory.unsafeInstance()` and `LZ4Factory.fastestJavaInstance()` are affected. - `LZ4Factory.fastestInstance()` uses the `nativeInstance` or `fastestJavaInstance` depending on platform. `LZ4Factory.fastestInstance().fastDecompressor()` is always affected, while `LZ4Factory.fastestInstance().safeDecompressor()` is affected only when JNI cannot be used (e.g. on unsupported platforms). Independent of this vulnerability, it is recommended that users migrate from `fastDecompressor` to `safeDecompressor`, as the latter is more performant (despite the name). The impact of this vulnerability depends on how user code interacts with the decompression API. Users that allocate a new destination buffer each time, or use only zeroed buffers, are not impacted. When the buffer is reused, however, the confidentiality impact can be severe. This vulnerability is marked as VC:H out of caution. ### Mitigation lz4-java 1.10.1 fixes this issue without requiring changes in user code. If you cannot upgrade to 1.10.1, you can mitigate this vulnerability by zeroing the output buffer before passing it to the decompression function. ### Relation to CVE‐2025‐12183 This CVE is a different attack than [CVE‐2025‐12183](https://sites.google.com/sonatype.com/vulnerabilities/cve-2025-12183), affecting different implementations with different impact. This new vulnerability was discovered by [CodeIntelligence](https://www.code-intelligence.com/) during research that followed up on CVE‐2025‐12183. Users are recommended to upgrade to 1.10.1 to fix both vulnerabilities.
- CERTFR-2026-AVI-1385Multiples vulnérabilités dans les produits VMwareFrançais2026-10-26vendor · certfrFR
also known as (4)
Other names and identifiers for this entity.
sources
Which sources assert this record, and when.
references (9)
External citations — patches, advisories, analysis.
- https://github.com/yawkat/lz4-java/commit/33d180cb70c4d93c80fb0dc3ab3002f457e93840cnnvd
- https://github.com/yawkat/lz4-java/releasesPatchcnnvd
- https://github.com/yawkat/lz4-java/security/advisories/GHSA-cmp6-m4wj-q63qcnnvd
- https://www.oracle.com/security-alerts/cpuapr2026.htmlcnnvd
- https://www.oracle.com/security-alerts/cpujan2026.htmlcnnvd
- https://github.com/yawkat/lz4-java/commit/33d180cb70c4d93c80fb0dc3ab3002f457e93840enisa_euvd
- https://github.com/yawkat/lz4-java/security/advisories/GHSA-cmp6-m4wj-q63qenisa_euvd
- https://github.com/yawkat/lz4-java/commit/33d180cb70c4d93c80fb0dc3ab3002f457e93840nvd
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