lz4_flex is a pure Rust implementation of LZ4 compression/decompression. In versions 0.11.5 and below, and 0.12.0, decompressing invalid LZ4 data can leak sensitive information from uninitialized memory or from previous decompression operations. The library fails to properly validate offset values during LZ4 match copy operations, allowing out-of-bounds reads from the output buffer. The block-based API functions (decompress_into, decompress_into_with_dict, and others when safe-decode is disabled) are affected, while all frame APIs are unaffected. The impact is potential exposure of sensitive data and secrets through crafted or malformed LZ4 input. This issue has been fixed in versions 0.11.6 and 0.12.1.
Weakness
The code transmits data to another actor, but a portion of the data includes sensitive information that should not be accessible to that actor.
Affected Software
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Lz4_flex | Pseitz | * | 0.11.6 (excluding) |
| Lz4_flex | Pseitz | 0.12.0 (including) | 0.12.0 (including) |
| Logging Subsystem for Red Hat OpenShift 6.2 | RedHat | openshift-logging/vector-rhel9:1776894389 | * |
| Logging Subsystem for Red Hat OpenShift 6.4 | RedHat | openshift-logging/vector-rhel9:1780052069 | * |
| Logging Subsystem for Red Hat OpenShift 6.5 | RedHat | openshift-logging/vector-rhel9:1777574710 | * |
| Red Hat OpenShift AI 3.3 | RedHat | rhoai/odh-llm-d-inference-scheduler-rhel9:1778263962 | * |
| Rust-lz4-flex | Ubuntu | upstream | * |
Potential Mitigations
- Compartmentalize the system to have “safe” areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area.
- Ensure that appropriate compartmentalization is built into the system design, and the compartmentalization allows for and reinforces privilege separation functionality. Architects and designers should rely on the principle of least privilege to decide the appropriate time to use privileges and the time to drop privileges.
Related Attack Patterns
- https://cwe.mitre.org/data/definitions/12.html
- https://cwe.mitre.org/data/definitions/217.html
- https://cwe.mitre.org/data/definitions/612.html
- https://cwe.mitre.org/data/definitions/613.html
- https://cwe.mitre.org/data/definitions/618.html
- https://cwe.mitre.org/data/definitions/619.html
- https://cwe.mitre.org/data/definitions/621.html
- https://cwe.mitre.org/data/definitions/622.html
- https://cwe.mitre.org/data/definitions/623.html
References
- https://github.com/PSeitz/lz4_flex/commit/055502ee5d297ecd6bf448ac91c055c7f6df9b6d
- https://github.com/PSeitz/lz4_flex/security/advisories/GHSA-vvp9-7p8x-rfvv
- https://rustsec.org/advisories/RUSTSEC-2026-0041.html
- https://access.redhat.com/errata/RHSA-2026:11800
- https://access.redhat.com/errata/RHSA-2026:16354
- https://access.redhat.com/errata/RHSA-2026:19712
- https://access.redhat.com/errata/RHSA-2026:22862
- https://access.redhat.com/security/cve/CVE-2026-32829
- https://bugzilla.redhat.com/show_bug.cgi?id=2448271
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-32829.json