Apache MINA: Improper Handling of Highly Compressed Data (Data Amplification)
CVE-2026-47321 is a high-severity improper handling of highly compressed data (data amplification) vulnerability in Apache MINA from Apache, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists versions 2.2.8, 2.1.13, 2.0.29 as the first without the flaw, so updating Apache MINA to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.49% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Apache MINA to 2.2.8 or 2.1.13 or 2.0.29, whichever matches your release line, or a later version.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Apache | Apache MINA | 2.2.0 up to, but not including, 2.2.8; 2.1.0 up to, but not including, 2.1.13; 2.0.0 up to, but not including, 2.0.29 | 2.2.8, 2.1.13, 2.0.29 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- NoneNo data is disclosed.
- Integrity
- NoneNothing can be modified.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. Scored by CNA (apache.org).
Official description
The CompressionFilter class uses ZLib to deflate and inflate data sent and received. When we inflate incoming data, the filter does not control the resulting size, and create a buffer no matter what. Some compressed data may have a compression ration greater than 1 thousand, leading to an exhaustion of the application memory, as we don't control the deflated size. The fix adds such a control by allowing the application developer to provide a fixed size limit, which when reached throws an exception. It also allows the user to provide a compression ratio that should not be exceeded, protected the application from small inflated files that inflate in gigantic files, but with a grace limit for the resulting size (1Mb) to avoid false positive (like a very small file inflating with a high ratio, but resulting with a acceptable size, like a few thousands bytes) For application using this feature, it is highly recommended to create the CompressionFilter and to pass the maximum limit as a forth constructor parameter, maxDecompressedSize: public CompressionFilter(final boolean compressInbound, final boolean compressOutbound, final int compressionLevel, final int maxDecompressedSize)Optionally one can also provide a maxDecompressRatio fifth parameter, and a decompressRatioMinSize sixth parameter to allow small inflated files with a high compression ratio to still be accepted. Here are the additional constructor: public CompressionFilter(final boolean compressInbound, final boolean compressOutbound, final int compressionLevel, final int maxDecompressedSize, final long maxDecompressRatio, final long decompressRatioMinSize) Also note that a fluent API has been added to spare the users the pain to call a constructor with that many parameters: CompressionFilter compressionFilter = new CompressionFilter() .setCompressionLevel(Zlib.COMPRESSION_MAX) .setMaxDecompressedSize(1_000_000) .setMaxDecompressRatio(100). .setDecompressRatioMinSize(100_000); Applications using Apache MINA are advised to upgrade and configure their CompressionFilter instance.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Handling of Highly Compressed Data (Data Amplification)
The product does not handle or incorrectly handles a compressed input with a very high compression ratio that produces a large output.
More Improper Handling of Highly Compressed Data (Data Amplification) vulnerabilities (CWE-409)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
References
Other references
Other vulnerabilities in Apache MINA
- 9.8 Critical severity
- 9.8 Critical severity
- 9.8 Critical severity
- 9.8 Critical severity
- 9.8 Critical severity
- 9.8 Critical severity
Recent Improper Handling of Highly Compressed Data (Data Amplification) vulnerabilities
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
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