---
id: CVE-2026-80892
title: 'erofs: cap LZMA stream pool size'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  erofs: cap LZMA stream pool size

  fs/erofs/decompressor_lzma.c sizes the module-global MicroLZMA stream
  pool from num_possible_cpus() when the lzma_streams module param…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 622ceaddb7649ca328832f50ba1400af778d75fa <
    682cb3ece37fc5141e73bc726ccf4adb833e5189
  - >-
    Linux >= 622ceaddb7649ca328832f50ba1400af778d75fa <
    e8b3d09aa8889dda9be9cbb3d2f0218c4b9acde4
  - >-
    Linux >= 622ceaddb7649ca328832f50ba1400af778d75fa <
    0c676903cb2a61992ded8e7907609cc6b0f11744
  - >-
    Linux >= 622ceaddb7649ca328832f50ba1400af778d75fa <
    5aaa06dfc10f8398c8807453dbec738ea9af10e4
  - >-
    Linux >= 622ceaddb7649ca328832f50ba1400af778d75fa <
    e52da169b8c0d19bb2d803f2a07fe0e5a00462d6
  - >-
    Linux >= 622ceaddb7649ca328832f50ba1400af778d75fa <
    c9b47e6b23114e939b17f818471c7a46e59006e7
  - Linux 5.16
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-11-06T17:04:39.997592Z'
published: '2026-09-04'
updated: '2026-11-06'
sourceUpdated: '2026-11-06T17:05:56.225Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-80892'
references:
  - url: 'https://git.kernel.org/stable/c/682cb3ece37fc5141e73bc726ccf4adb833e5189'
  - url: 'https://git.kernel.org/stable/c/e8b3d09aa8889dda9be9cbb3d2f0218c4b9acde4'
  - url: 'https://git.kernel.org/stable/c/0c676903cb2a61992ded8e7907609cc6b0f11744'
  - url: 'https://git.kernel.org/stable/c/5aaa06dfc10f8398c8807453dbec738ea9af10e4'
  - url: 'https://git.kernel.org/stable/c/e52da169b8c0d19bb2d803f2a07fe0e5a00462d6'
  - url: 'https://git.kernel.org/stable/c/c9b47e6b23114e939b17f818471c7a46e59006e7'
tags:
  - cve.org
epss: 0.00173
epssPercentile: 0.06691
ingestedAt: '2026-11-06T18:00:12.527Z'
---

## Overview

In the Linux kernel, the following vulnerability has been resolved:

erofs: cap LZMA stream pool size

fs/erofs/decompressor_lzma.c sizes the module-global MicroLZMA stream
pool from num_possible_cpus() when the lzma_streams module parameter is
unset, then z_erofs_load_lzma_config() preallocates one image-supplied
dictionary per stream, accepting dictionaries up to 8 MiB.  On high-CPU
systems, a small EROFS image can pin hundreds of MiB of vmalloc-backed
decoder state until the erofs module is unloaded.

Impact: An EROFS image mounted by the system can pin up to 8 MiB of
vmalloc memory per LZMA stream, either as intended or unexpectedly.

Bound the default stream count by a new
CONFIG_EROFS_FS_ZIP_LZMA_DEFAULT_MAX_STREAMS option, default 16, so the
worst-case default preallocation is 128 MiB if the number of CPUs is no
less than 16 while preserving the existing per-image dictionary limit.
An explicit lzma_streams module parameter is still honoured as-is, so
administrators who deliberately size the pool are not affected.

## Affected

- `Linux >= 622ceaddb7649ca328832f50ba1400af778d75fa < 682cb3ece37fc5141e73bc726ccf4adb833e5189`
- `Linux >= 622ceaddb7649ca328832f50ba1400af778d75fa < e8b3d09aa8889dda9be9cbb3d2f0218c4b9acde4`
- `Linux >= 622ceaddb7649ca328832f50ba1400af778d75fa < 0c676903cb2a61992ded8e7907609cc6b0f11744`
- `Linux >= 622ceaddb7649ca328832f50ba1400af778d75fa < 5aaa06dfc10f8398c8807453dbec738ea9af10e4`
- `Linux >= 622ceaddb7649ca328832f50ba1400af778d75fa < e52da169b8c0d19bb2d803f2a07fe0e5a00462d6`
- `Linux >= 622ceaddb7649ca328832f50ba1400af778d75fa < c9b47e6b23114e939b17f818471c7a46e59006e7`
- `Linux 5.16`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.