vulnerability / NVI-00017694 / Revision 1
MessagePack's LZ4 decompression may fail with AccessViolationException after dereferencing memory from bad input
GitHub lists this reviewed advisory for MessagePack, MessagePack. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.
This report has not inspected your inventory, configuration, deployed build, reachability or evidence. A catalog listing and a severity score do not establish exposure or compromise.
01 / Meaning
Why it matters
Published affected context helps an owner decide what evidence to gather. This report has not examined your application.
8.2 high
GitHub source severity; exploitability and local consequence require separate evidence.
As of · GitHub Advisory Database
02 / Applicability
The affected context
Affected versions, configuration prerequisites and known exclusions are public. Confirm each one against the deployed service.
MessagePack
source listed< 2.5.301
### Impact A vulnerability exists in the optional LZ4 decompression path used by MessagePack compression modes `Lz4Block` and `Lz4BlockArray`. The decoder implementation is based on a deprecated fast-decompression algorithm that does not take a source-length bound. A remote attacker can send a crafted MessagePack payload with manipulated LZ4 token/length fields to force out-of-bounds reads from the compressed input buffer. In affected environments, this can trigger an `AccessViolationException` during decompression, causing process termination (denial of service). Under some conditions, limited unintended memory disclosure from over-read data may also be possible before failure. This issue affects applications that deserialize untrusted data while LZ4 compression is enabled. ### Patches The v2 versions are patched as of 2.5.301. The v3 versions are patched as of 3.1.7. ### Workarounds Instead of upgrading, an application may take the following precautions: 1. Disable LZ4 compression for untrusted input paths (`Lz4Block`, `Lz4BlockArray`). 2. Only accept compressed payloads from strongly trusted producers. 3. Isolate deserialization in a separate process/container with resta
MessagePack
source listed>= 3.0.214-rc.1, < 3.1.7
### Impact A vulnerability exists in the optional LZ4 decompression path used by MessagePack compression modes `Lz4Block` and `Lz4BlockArray`. The decoder implementation is based on a deprecated fast-decompression algorithm that does not take a source-length bound. A remote attacker can send a crafted MessagePack payload with manipulated LZ4 token/length fields to force out-of-bounds reads from the compressed input buffer. In affected environments, this can trigger an `AccessViolationException` during decompression, causing process termination (denial of service). Under some conditions, limited unintended memory disclosure from over-read data may also be possible before failure. This issue affects applications that deserialize untrusted data while LZ4 compression is enabled. ### Patches The v2 versions are patched as of 2.5.301. The v3 versions are patched as of 3.1.7. ### Workarounds Instead of upgrading, an application may take the following precautions: 1. Disable LZ4 compression for untrusted input paths (`Lz4Block`, `Lz4BlockArray`). 2. Only accept compressed payloads from strongly trusted producers. 3. Isolate deserialization in a separate process/container with resta
03 / Response
What to do next
- investigate
Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.
Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system. GitHub Advisory Database
A fixed release is not deployment evidence.
Check current vendor support and compatibility. After making a change, verify the deployed build and relevant runtime conditions. Keep the evidence, owner and time. An updated lockfile alone does not prove what is running.
04 / Limits
What this report cannot establish
- Customer inventory, deployment, reachability and exploitation have not been inspected.
05 / Provenance
Sources you can inspect
Each assertion retains its source. Mirrored records may repeat one underlying publisher; additional links are not independent corroboration.
- GHSA-hv8m-jj95-wg3x ↗
GitHub Advisory Database · vendor advisory
Observed . GitHub Advisory Database; CC-BY-4.0. Each advisory links its original attribution. Null normalizes fields.
Public revision history
Only published revisions appear here. Routine fetches do not create a material-change event.
- Revision 1 ·
First indexed by Null; source disclosure date is shown separately.