VulnerabilityPublished 21 Sep 2026

CVE-2026-47321: Apache MINA · Improper Handling of Highly Compressed Data – Data Amplification

Affects Apache MINASource CVE Database V5

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Not known to be exploited · CVSS 7.5 High · fixed in 2.2.8 : patch Apache MINA soon.

Data as of 5 Nov 2026, 00:01 UTC

CVSS 3.1 base score

7.5High

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.4% chance of exploitation in 30 days – higher than 42% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 2.2.8, 2.1.13, 2.0.29

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: None
Availability: High

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: High: There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 21 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 5 Nov 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

ghsa-3c8x-fp36-75xv

What to do

Upgrade Apache to 2.2.8, 2.1.13 or 2.0.29.

Affected software

Product	Affected	Fixed in
Apache Software FoundationApache MINA	Affected >=2.2.0 <2.2.8	Fixed in 2.2.8
Apache Software FoundationApache MINA	Affected >=2.1.0 <2.1.13	Fixed in 2.1.13
Apache Software FoundationApache MINA	Affected >=2.0.0 <2.0.29	Fixed in 2.0.29
MavenApache Software Foundation/org.apache.mina:mina-filter-compression`pkg:maven/Apache Software Foundation/org.apache.mina:mina-filter-compression`Other threats	Affected >=2.2.0 <2.2.8 >=2.1.0 <2.1.13 >=2.0.0 <2.0.29	Fixed in 2.2.8 2.1.13 2.0.29

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

A fix is available by upgrading to a version of Apache MINA that includes the patched CompressionFilter class. Application developers should instantiate CompressionFilter with parameters specifying a maximum decompressed size and optionally a maximum decompression ratio to prevent excessive memory usage. For example, using the constructor with maxDecompressedSize and maxDecompressRatio parameters or the fluent API to set these limits is recommended. No other vendor advisory or patch link was provided, so check the Apache MINA project for the official fixed versions and upgrade accordingly.

Description

CVE-2026-47321 is a high-severity vulnerability in Apache MINA's CompressionFilter class where inflated data size is not properly controlled. This can lead to excessive memory consumption due to data amplification from highly compressed inputs. The vulnerability affects Apache MINA versions >=2.0.0 <2.0.29, >=2.1.0 <2.1.13, and >=2.2.0 <2.2.8. The fix introduces parameters to limit maximum decompressed size and decompression ratio, preventing memory exhaustion. Users are advised to upgrade and configure CompressionFilter accordingly.

Impact

An attacker can send specially crafted compressed data that decompresses to a very large size, causing the application to allocate excessive memory and potentially crash or become unresponsive. This results in a denial of service (DoS) condition. The vulnerability does not affect confidentiality or integrity but impacts availability due to resource exhaustion.

Summary

The CompressionFilter class in Apache MINA uses ZLib for data compression and decompression. When inflating incoming compressed data, the filter previously did not limit the size of the decompressed output, allowing attackers to supply highly compressed data that decompresses to a very large size, potentially exhausting application memory. The fix adds constructor parameters and fluent API methods to set a maximum decompressed size and maximum decompression ratio, throwing exceptions if these limits are exceeded. This protects applications from data amplification attacks that exploit excessive decompression resource consumption.

CWE-409Improper Handling of Highly Compressed Data (Data Amplification) (opens in a new tab)
Base weakness
The product does not handle or incorrectly handles a compressed input with a very high compression ratio that produces a large output.
OWASP Cheat Sheets
File Upload (opens in a new tab)
OWASP ASVS 4.0.3
V12.1.2 (opens in a new tab)
V12.1.1 (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
CWE-789Memory Allocation with Excessive Size Value (opens in a new tab)
Variant weakness
The product allocates memory based on an untrusted, large size value, but it does not ensure that the size is within expected limits, allowing arbitrary amounts of memory to be allocated.
Implementation · Architecture and Design
Perform adequate input validation against any value that influences the amount of memory that is allocated. Define an appropriate strategy for handling requests that exceed the limit, and consider supporting a configuration option so that the administrator can extend the amount of memory to be used if necessary.
Operation
Run your program using system-provided resource limits for memory. This might still cause the program to crash or exit, but the impact to the rest of the system will be minimized.
OWASP Cheat Sheets
Abuse Case (opens in a new tab)
OWASP ASVS 4.0.3
V8.1.4 (opens in a new tab)
V13.4.1 (opens in a new tab)
V11.1.4 (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 18 Oct 2026, 01:22 UTC

WeaknessesCWE-409, CWE-789

Technical details

References

Community reviews

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