vulnerability / NVI-00013906 / Revision 1
MySQL2: Unbounded zlib inflate in compressed MySQL protocol handler allows decompression-bomb DoS
GitHub lists this reviewed advisory for mysql2. 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.
5.9 medium
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.
mysql2
source listed<= 3.23.0
## Vulnerability Details **File**: `lib/compressed_protocol.js` **Line**: 43 (`zlib.inflate(body, (err, data) => { ... })` inside `handleCompressedPacket`) ### Root Cause When a connection is created with `compress: true` (and the server advertises `CLIENT_COMPRESS`), every incoming packet is unwrapped by `handleCompressedPacket()` in `lib/compressed_protocol.js`, which calls: ```js zlib.inflate(body, (err, data) => { ... }); ``` No options object (in particular, no `maxOutputLength`) is passed. Node's zlib convenience methods default `maxOutputLength` to `buffer.kMaxLength`, which on this platform is `Number.MAX_SAFE_INTEGER` — i.e. effectively unbounded until the process runs out of memory. The 3-byte "length of payload before compression" field in the compressed-packet header is read (`packet.readInt24()`) but is only used to branch on `!== 0`; it is never used to cap or validate the actual inflate output size, and the real decompressed size is determined purely by the attacker-supplied deflate stream. Because DEFLATE can reach compression ratios over 1000:1 for crafted repetitive input, an attacker who controls (or MITMs, on a non-TLS connection) the MySQL server endpoint
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.
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04 / Limits
What this report cannot establish
- Customer inventory, deployment, reachability and exploitation have not been inspected.
05 / Provenance
Sources you can inspect
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- GHSA-rgwj-5xj2-c3m3 ↗
GitHub Advisory Database · vendor advisory
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Public revision history
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- Revision 1 ·
First indexed by Null; source disclosure date is shown separately.