erofs: disable LZ4 rolling decompression for now
In the Linux kernel, the following vulnerability has been resolved: erofs: disable LZ4 rolling decompression for now LZ4 rolling decompression [1] was introduced to reduce the memory footprint of temporary pages: For many cases, it is needed for users to read small data within a compressed extent (pcluster), either due to random small read, or since uptodate folios (typically order-0) cannot be reused for decompression again since decompression algorithm refills already-uptodate folios. Rolling decompression works because LZ4 is LZ77-based and only refers to the most recent 64 KiB of decompressed data, so in theory only a bounded rolling window of temporary pages is needed when decompressing. It can save a lot of temporary memory, e.g. 601,960-byte data can be compressed into a 256k LZ4 compressed extent, which means it needs 146 extra pages per request in the worst case if rolling decompression is disabled. However, the upstream LZ4 implementation is not under EROFS' control: For example, the literal copy memmove() may still **copy long literals backward** on x86 based on the address comparison even when the source and destination ranges do not overlap (IOWs, inline decompression doesn't need to be considered here). That breaks the rolling assumption and makes the optimization broken. Disable it for now to make sure the data correctness first since EROFS is used everywhere now: The rolling window approach can be revived once we either ensure that the official LZ4 code always
CVE-2026-98067
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-98067
Linux
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Linux
Source reference: /containers/cna/affected/1/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "8e6c8fa9f2e95c88a642521a5da19a8e31748846",
"lessThan": "dcc5e6c9e4d06fe73fc61e730ee3e51dd115a4d8",
"versionType": "git"
},
{
"status": "affected",
"version": "8e6c8fa9f2e95c88a642521a5da19a8e31748846",
"lessThan": "d923e53472b468a50a6cf41341531d5170c68371",
"versionType": "git"
},
{
"status": "affected",
"version": "8e6c8fa9f2e95c88a642521a5da19a8e31748846",
"lessThan": "ec52dfed7b14514ed97ee71161e4cf4cfe2fbff2",
"versionType": "git"
},
{
"status": "affected",
"version": "8e6c8fa9f2e95c88a642521a5da19a8e31748846",
"lessThan": "c9a2db4b9950b59c571258e4bae74c271f62dd66",
"versionType": "git"
},
{
"status": "affected",
"version": "8e6c8fa9f2e95c88a642521a5da19a8e31748846",
"lessThan": "82e664cf1219c459c33aae931b222cf951af9cb7",
"versionType": "git"
}
],
"programFiles": [
"fs/erofs/decompressor.c",
"fs/erofs/internal.h",
"fs/erofs/zdata.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "5.13"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "5.13",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.6.160",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.114",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.53",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.2.7",
"versionType": "semver",
"lessThanOrEqual": "7.2.*"
},
{
"status": "unaffected",
"version": "7.3",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"fs/erofs/decompressor.c",
"fs/erofs/internal.h",
"fs/erofs/zdata.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-98067
Source reference:
/cveMetadata/cveId
Publisher severity
No explicit severity was provided.
- Event
- #48844 · Revision 1
- Added to Heist Feed
- Publisher date