CWE-409
AllowedImproper Handling of Highly Compressed Data (Data Amplification)
Abstraction: Base · Status: Incomplete
The product does not handle or incorrectly handles a compressed input with a very high compression ratio that produces a large output.
274 vulnerabilities reference this CWE, most recent first.
GHSA-X7P2-XRMV-3P2X
Vulnerability from github – Published: 2026-09-01 21:31 – Updated: 2026-09-01 21:31Improper Handling of Highly Compressed Data (CWE-409) in Kibana can lead to a denial of service via Excessive Allocation (CAPEC-130). An authenticated user holding Streams management privileges could supply specially crafted content that expands to a far larger volume of data during processing, exhausting the memory available to Kibana. The Kibana process is terminated by the host and remains unavailable to all users until the service is restarted.
{
"affected": [],
"aliases": [
"CVE-2026-72628"
],
"database_specific": {
"cwe_ids": [
"CWE-409"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-09-01T20:17:16Z",
"severity": "MODERATE"
},
"details": "Improper Handling of Highly Compressed Data (CWE-409) in Kibana can lead to a denial of service via Excessive Allocation (CAPEC-130). An authenticated user holding Streams management privileges could supply specially crafted content that expands to a far larger volume of data during processing, exhausting the memory available to Kibana. The Kibana process is terminated by the host and remains unavailable to all users until the service is restarted.",
"id": "GHSA-x7p2-xrmv-3p2x",
"modified": "2026-09-01T21:31:47Z",
"published": "2026-09-01T21:31:47Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-72628"
},
{
"type": "WEB",
"url": "https://discuss.elastic.co/t/kibana-8-19-21-9-4-6-9-5-2-security-update-esa-2026-125/390090"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
}
]
}
GHSA-X8V2-478Q-2HVG
Vulnerability from github – Published: 2026-10-08 16:49 – Updated: 2026-10-08 16:49Impact
With WebSocket compression enabled, the client inflates permessage-deflate messages with no limit on the decompressed size. It installed Netty's shared WebSocketClientCompressionHandler.INSTANCE, whose inflater is unbounded, and webSocketMaxFrameSize and webSocketMaxBufferSize only bound the compressed bytes, because the frame aggregator sits in front of the inflater.
A malicious or compromised WebSocket server, or anyone on the path of a ws:// connection, can therefore send a message of about 2 MiB that inflates to about 2 GiB, the most a Netty buffer can hold. The client then copies the inflated message again to hand it to the listener. That exhausts the heap of a typically sized JVM. Netty catches the resulting OutOfMemoryError and closes that connection, but while the buffer is live any other allocation in the process can fail too, and a server that keeps sending such messages, on one connection or several, keeps the client at heap exhaustion.
Who is Impacted
Only applications that enable WebSocket compression with setEnablewebSocketCompression(true), which is off by default, and connect to a WebSocket server that is untrusted, compromised, or reached over cleartext ws://.
Affected versions
- 3.x: up to and including 3.0.13
- 2.x: from 2.2.0, when WebSocket compression was added, up to and including 2.16.1
Patches
Fixed in 3.0.14. A new setting, webSocketMaxDecompressedFrameSize (setWebSocketMaxDecompressedFrameSize, or the org.asynchttpclient.webSocketMaxDecompressedFrameSize property), bounds how far a message may inflate, and a message that would go past it fails the connection. It defaults to 128000000 bytes, the same as webSocketMaxBufferSize, so a message is bounded alike whether or not it was compressed; a compressed message that inflates past that, which was accepted before, now fails the connection. With aggregateWebSocketFrameFragments turned off, the bound applies to each frame instead, and fragments are delivered one at a time. Set it lower if you enable compression and do not expect large messages. 0 disables the limit.
The 2.x line is end of life and will not receive a fix. Upgrade to 3.0.14.
Workarounds
Leave WebSocket compression disabled, which is the default.
Details
After the handshake the inbound pipeline is ws-decoder, ws-aggregator, PerMessageDeflateDecoder, ahc-ws: the aggregator, which enforces webSocketMaxBufferSize, sees each message before it is inflated. WebSocketClientCompressionHandler.INSTANCE is built with maxAllocation = 0, which Netty treats as unbounded, and Netty has deprecated it in favour of a constructor that takes a limit. RFC 6455 Section 10.4 asks an implementation to limit the size of a message after reassembly, and under RFC 7692 Section 6.2 the message delivered to the application is the decompressed payload.
This is a different path from the HTTP response decompression fixed under CVE-2026-85721, which never reached the WebSocket pipeline.
Attribution
AI-assisted tools were used to support discovery and analysis.
{
"affected": [
{
"database_specific": {
"last_known_affected_version_range": "\u003c= 3.0.13"
},
"package": {
"ecosystem": "Maven",
"name": "org.asynchttpclient:async-http-client"
},
"ranges": [
{
"events": [
{
"introduced": "3.0.0"
},
{
"fixed": "3.0.14"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"package": {
"ecosystem": "Maven",
"name": "org.asynchttpclient:async-http-client"
},
"ranges": [
{
"events": [
{
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},
{
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}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2026-107227"
],
"database_specific": {
"cwe_ids": [
"CWE-400",
"CWE-409"
],
"github_reviewed": true,
"github_reviewed_at": "2026-10-08T16:49:53Z",
"nvd_published_at": "2026-10-07T21:17:14Z",
"severity": "HIGH"
},
"details": "### Impact\n\nWith WebSocket compression enabled, the client inflates `permessage-deflate` messages with no limit on the decompressed size. It installed Netty\u0027s shared `WebSocketClientCompressionHandler.INSTANCE`, whose inflater is unbounded, and `webSocketMaxFrameSize` and `webSocketMaxBufferSize` only bound the compressed bytes, because the frame aggregator sits in front of the inflater.\n\nA malicious or compromised WebSocket server, or anyone on the path of a `ws://` connection, can therefore send a message of about 2 MiB that inflates to about 2 GiB, the most a Netty buffer can hold. The client then copies the inflated message again to hand it to the listener. That exhausts the heap of a typically sized JVM. Netty catches the resulting `OutOfMemoryError` and closes that connection, but while the buffer is live any other allocation in the process can fail too, and a server that keeps sending such messages, on one connection or several, keeps the client at heap exhaustion.\n\n### Who is Impacted\n\nOnly applications that enable WebSocket compression with `setEnablewebSocketCompression(true)`, which is off by default, and connect to a WebSocket server that is untrusted, compromised, or reached over cleartext `ws://`.\n\n### Affected versions\n\n* 3.x: up to and including 3.0.13\n* 2.x: from 2.2.0, when WebSocket compression was added, up to and including 2.16.1\n\n### Patches\n\nFixed in 3.0.14. A new setting, `webSocketMaxDecompressedFrameSize` (`setWebSocketMaxDecompressedFrameSize`, or the `org.asynchttpclient.webSocketMaxDecompressedFrameSize` property), bounds how far a message may inflate, and a message that would go past it fails the connection. It defaults to 128000000 bytes, the same as `webSocketMaxBufferSize`, so a message is bounded alike whether or not it was compressed; a compressed message that inflates past that, which was accepted before, now fails the connection. With `aggregateWebSocketFrameFragments` turned off, the bound applies to each frame instead, and fragments are delivered one at a time. Set it lower if you enable compression and do not expect large messages. `0` disables the limit.\n\nThe 2.x line is end of life and will not receive a fix. Upgrade to 3.0.14.\n\n### Workarounds\n\nLeave WebSocket compression disabled, which is the default.\n\n### Details\n\nAfter the handshake the inbound pipeline is `ws-decoder`, `ws-aggregator`, `PerMessageDeflateDecoder`, `ahc-ws`: the aggregator, which enforces `webSocketMaxBufferSize`, sees each message before it is inflated. `WebSocketClientCompressionHandler.INSTANCE` is built with `maxAllocation = 0`, which Netty treats as unbounded, and Netty has deprecated it in favour of a constructor that takes a limit. RFC 6455 Section 10.4 asks an implementation to limit the size of a message after reassembly, and under RFC 7692 Section 6.2 the message delivered to the application is the decompressed payload.\n\nThis is a different path from the HTTP response decompression fixed under CVE-2026-85721, which never reached the WebSocket pipeline.\n\n### Attribution\n\nAI-assisted tools were used to support discovery and analysis.",
"id": "GHSA-x8v2-478q-2hvg",
"modified": "2026-10-08T16:49:54Z",
"published": "2026-10-08T16:49:53Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/AsyncHttpClient/async-http-client/security/advisories/GHSA-x8v2-478q-2hvg"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-107227"
},
{
"type": "WEB",
"url": "https://github.com/AsyncHttpClient/async-http-client/commit/b61637f30327f314b7693418f12ce141ac6b2b30"
},
{
"type": "PACKAGE",
"url": "https://github.com/AsyncHttpClient/async-http-client"
},
{
"type": "WEB",
"url": "https://github.com/AsyncHttpClient/async-http-client/releases/tag/async-http-client-project-3.0.14"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
}
],
"summary": "AsyncHttpClient: Unbounded WebSocket permessage-deflate decompression enables a decompression-bomb denial of service when compression is enabled"
}
GHSA-XG43-5579-QW6V
Vulnerability from github – Published: 2026-07-15 23:30 – Updated: 2026-07-15 23:30Impact
adawolfa/isdoc reads ISDOC invoices from ISDOCX (ZIP) archives and from PDF files with embedded ISDOC documents and supplements. Affected versions inflate ZIP entries and read embedded files without validating their uncompressed size, so a small crafted file can amplify into gigabytes:
- ISDOCX decompression bomb —
getFromName()inflates the ISDOC document and binary supplements with no size cap. saveTo()disk-fill — the supplement copy loop writes inflated bytes to disk with no running byte budget, so a bomb can exhaust disk even if the central-directory size is under-reported.- PDF embedded files — an embedded file whose declared
Lengthis enormous is read and digested with no upper bound.
Exploitation requires the application to parse an attacker-supplied .isdocx or .pdf (the typical use is generating files or parsing files from trusted vendors, so a user must be induced to process a malicious file). When that happens the process can be driven to exhaust memory or disk, causing denial of service. There is no confidentiality or integrity impact — availability only.
Patches
Fixed in 1.4.3, 1.5.1, 1.6.1 and 2.0.0. The readers now:
- read the uncompressed size from the ZIP central directory (
statName()) and reject entries over a cap before inflating — 256 KB (DocumentSizeLimit) for the ISDOC document, 32 MB (SizeLimit) for supplements; - enforce a running byte budget in
saveTo()and unlink the partial file on overflow; - reject PDF-embedded files whose declared
Lengthexceeds 256 MB before reading or digesting them.
New exceptions ReaderException::zipEntryTooLarge(), SupplementException::supplementTooLarge() and ReaderException::pdfSupplementTooLarge() surface the rejection.
Unsupported versions
Versions before 1.4.0 (the 1.0–1.3 lines) are also affected and will not receive a fix, because they target end-of-life PHP. Users on those lines should upgrade to a maintained release — 1.4.3, 1.5.1, 1.6.1, or 2.0.0.
Workarounds
No code-level workaround exists in affected versions; upgrading is the fix. As mitigation, restrict parsing to trusted input, or enforce an external size / decompression limit (validate ZIP entry sizes, cap process memory) before handing files to the library.
Resources
{
"affected": [
{
"package": {
"ecosystem": "Packagist",
"name": "adawolfa/isdoc"
},
"ranges": [
{
"events": [
{
"introduced": "1.6.0"
},
{
"fixed": "1.6.1"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"package": {
"ecosystem": "Packagist",
"name": "adawolfa/isdoc"
},
"ranges": [
{
"events": [
{
"introduced": "1.5.0"
},
{
"fixed": "1.5.1"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"package": {
"ecosystem": "Packagist",
"name": "adawolfa/isdoc"
},
"ranges": [
{
"events": [
{
"introduced": "1.4.0"
},
{
"fixed": "1.4.3"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"database_specific": {
"last_known_affected_version_range": "\u003c 1.4.0"
},
"package": {
"ecosystem": "Packagist",
"name": "adawolfa/isdoc"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [],
"database_specific": {
"cwe_ids": [
"CWE-400",
"CWE-409"
],
"github_reviewed": true,
"github_reviewed_at": "2026-07-15T23:30:55Z",
"nvd_published_at": null,
"severity": "MODERATE"
},
"details": "### Impact\n\n`adawolfa/isdoc` reads ISDOC invoices from ISDOCX (ZIP) archives and from PDF files with embedded ISDOC documents and supplements. Affected versions inflate ZIP entries and read embedded files **without validating their uncompressed size**, so a small crafted file can amplify into gigabytes:\n\n- **ISDOCX decompression bomb** \u2014 `getFromName()` inflates the ISDOC document and binary supplements with no size cap.\n- **`saveTo()` disk-fill** \u2014 the supplement copy loop writes inflated bytes to disk with no running byte budget, so a bomb can exhaust disk even if the central-directory size is under-reported.\n- **PDF embedded files** \u2014 an embedded file whose declared `Length` is enormous is read and digested with no upper bound.\n\nExploitation requires the application to parse an attacker-supplied `.isdocx` or `.pdf` (the typical use is generating files or parsing files from trusted vendors, so a user must be induced to process a malicious file). When that happens the process can be driven to exhaust memory or disk, causing denial of service. There is **no confidentiality or integrity impact** \u2014 availability only.\n\n### Patches\n\nFixed in **1.4.3**, **1.5.1**, **1.6.1** and **2.0.0**. The readers now:\n\n- read the uncompressed size from the ZIP central directory (`statName()`) and reject entries over a cap **before inflating** \u2014 256 KB (`DocumentSizeLimit`) for the ISDOC document, 32 MB (`SizeLimit`) for supplements;\n- enforce a running byte budget in `saveTo()` and unlink the partial file on overflow;\n- reject PDF-embedded files whose declared `Length` exceeds 256 MB before reading or digesting them.\n\nNew exceptions `ReaderException::zipEntryTooLarge()`, `SupplementException::supplementTooLarge()` and `ReaderException::pdfSupplementTooLarge()` surface the rejection.\n\n### Unsupported versions\n\nVersions **before 1.4.0** (the 1.0\u20131.3 lines) are also affected and will **not** receive a fix, because they target end-of-life PHP. Users on those lines should upgrade to a maintained release \u2014 1.4.3, 1.5.1, 1.6.1, or 2.0.0.\n\n### Workarounds\n\nNo code-level workaround exists in affected versions; upgrading is the fix. As mitigation, restrict parsing to trusted input, or enforce an external size / decompression limit (validate ZIP entry sizes, cap process memory) before handing files to the library.\n\n### Resources\n\n- Decompression-bomb fix: commit [`935fb2a`](https://github.com/adawolfa/isdoc/commit/935fb2aa41ceddfcf43174a61a36ec620611a105) (backported, released as 1.4.3 / 1.5.1 / 1.6.1) and [`02a1012`](https://github.com/adawolfa/isdoc/commit/02a10123a3d5fd92950b8e4952959317c0a18952) (master, released as 2.0.0).\n- CWE-409 (Improper Handling of Highly Compressed Data), CWE-400 (Uncontrolled Resource Consumption).",
"id": "GHSA-xg43-5579-qw6v",
"modified": "2026-07-15T23:30:55Z",
"published": "2026-07-15T23:30:55Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/adawolfa/isdoc/security/advisories/GHSA-xg43-5579-qw6v"
},
{
"type": "WEB",
"url": "https://github.com/adawolfa/isdoc/commit/02a10123a3d5fd92950b8e4952959317c0a18952"
},
{
"type": "WEB",
"url": "https://github.com/adawolfa/isdoc/commit/935fb2aa41ceddfcf43174a61a36ec620611a105"
},
{
"type": "PACKAGE",
"url": "https://github.com/adawolfa/isdoc"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
}
],
"summary": "adawolfa/isdoc: Uncontrolled resource consumption (decompression bomb) when reading untrusted ISDOCX or PDF files"
}
GHSA-XV6H-R36F-3GP5
Vulnerability from github – Published: 2026-03-18 06:31 – Updated: 2026-10-06 18:31A flaw was found in Keycloak. An unauthenticated remote attacker can trigger an application level Denial of Service (DoS) by sending a highly compressed SAMLRequest through the SAML Redirect Binding. The server fails to enforce size limits during DEFLATE decompression, leading to an OutOfMemoryError (OOM) and subsequent process termination. This vulnerability allows an attacker to disrupt the availability of the service.
{
"affected": [
{
"package": {
"ecosystem": "Maven",
"name": "org.keycloak:keycloak-saml-adapter-core"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "26.5.4"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"package": {
"ecosystem": "Maven",
"name": "org.keycloak:keycloak-saml-core"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "26.5.4"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"package": {
"ecosystem": "Maven",
"name": "org.keycloak:keycloak-services"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "26.5.4"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2026-2575"
],
"database_specific": {
"cwe_ids": [
"CWE-409"
],
"github_reviewed": true,
"github_reviewed_at": "2026-03-18T20:19:33Z",
"nvd_published_at": "2026-03-18T04:17:16Z",
"severity": "MODERATE"
},
"details": "A flaw was found in Keycloak. An unauthenticated remote attacker can trigger an application level Denial of Service (DoS) by sending a highly compressed SAMLRequest through the SAML Redirect Binding. The server fails to enforce size limits during DEFLATE decompression, leading to an OutOfMemoryError (OOM) and subsequent process termination. This vulnerability allows an attacker to disrupt the availability of the service.",
"id": "GHSA-xv6h-r36f-3gp5",
"modified": "2026-10-06T18:31:15Z",
"published": "2026-03-18T06:31:20Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-2575"
},
{
"type": "WEB",
"url": "https://github.com/keycloak/keycloak/issues/46372"
},
{
"type": "WEB",
"url": "https://github.com/keycloak/keycloak/commit/4f90ef67f698dfb45df0d2f4981271a7c8b47f04"
},
{
"type": "WEB",
"url": "https://access.redhat.com/errata/RHSA-2026:3947"
},
{
"type": "WEB",
"url": "https://access.redhat.com/errata/RHSA-2026:3948"
},
{
"type": "WEB",
"url": "https://access.redhat.com/errata/RHSA-2026:76128"
},
{
"type": "WEB",
"url": "https://access.redhat.com/errata/RHSA-2026:76129"
},
{
"type": "WEB",
"url": "https://access.redhat.com/errata/RHSA-2026:76130"
},
{
"type": "WEB",
"url": "https://access.redhat.com/errata/RHSA-2026:76132"
},
{
"type": "WEB",
"url": "https://access.redhat.com/errata/RHSA-2026:76134"
},
{
"type": "WEB",
"url": "https://access.redhat.com/security/cve/CVE-2026-2575"
},
{
"type": "WEB",
"url": "https://bugzilla.redhat.com/show_bug.cgi?id=2440149"
},
{
"type": "PACKAGE",
"url": "https://github.com/keycloak/keycloak"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L",
"type": "CVSS_V3"
}
],
"summary": "Keycloak: Denial of Service due to excessive SAMLRequest decompression"
}
No mitigation information available for this CWE.
No CAPEC attack patterns related to this CWE.