CVE-2026-43166 (GCVE-0-2026-43166)

Vulnerability from cvelistv5 – Published: 2026-05-06 11:27 – Updated: 2026-08-05 12:26
VLAI
Title
erofs: fix interlaced plain identification for encoded extents
Summary
In the Linux kernel, the following vulnerability has been resolved: erofs: fix interlaced plain identification for encoded extents Only plain data whose start position and on-disk physical length are both aligned to the block size should be classified as interlaced plain extents. Otherwise, it must be treated as shifted plain extents. This issue was found by syzbot using a crafted compressed image containing plain extents with unaligned physical lengths, which can cause OOB read in z_erofs_transform_plain().
Severity
7.1 (High)
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 1d191b4ca51d73699cb127386b95ac152af2b930 , < 9d5a97bc71ed5783687705c708454c4453aa91d1 (git)
Affected: 1d191b4ca51d73699cb127386b95ac152af2b930 , < d3790f26d38606f020212486359b84632c19d08b (git)
Affected: 1d191b4ca51d73699cb127386b95ac152af2b930 , < 4a2d046e4b13202a6301a993961f5b30ae4d7119 (git)
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Linux Linux Affected: 6.15
Unaffected: 0 , < 6.15 (semver)
Unaffected: 6.18.16 , ≤ 6.18.* (semver)
Unaffected: 6.19.6 , ≤ 6.19.* (semver)
Unaffected: 7.0 , ≤ * (original_commit_for_fix)
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{
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              "value": "AV:L - The vulnerable path is reached by local VFS operations on a crafted EROFS image: mount the image and read/open a compressed file so EROFS performs readahead/decompression. There is no direct network, adjacent, or physical protocol entry point in EROFS itself.\nAC:L - The trigger is deterministic malformed extent metadata with an aligned physical start and unaligned encoded length; syzbot reproduced it with a crafted image and ordinary mount/open/read activity. No attacker-uncontrolled race or fragile timing condition is required.\nPR:N - An attacker can craft and supply the malicious EROFS image without privileges; the privileged filesystem mount/read can be performed by an interacting victim or image-processing environment. EROFS is not marked FS_USERNS_MOUNT, so a purely self-triggered local mount would require CAP_SYS_ADMIN, but the higher-severity defensible scenario is malicious media/image handling.\nUI:R - Exploitation requires some user or system action to mount or otherwise process the crafted EROFS image and read/open the affected file. The vulnerable code is not reached passively before the image is mounted/read.\nS:U - The bug is in kernel filesystem parsing/decompression and affects the same kernel security authority. It does not cross a hypervisor, VM, IOMMU, or sandbox boundary by itself.\nC:H - The bug causes a slab/out-of-bounds read of up to a page-sized copy in z_erofs_transform_plain(), and the copied bytes are placed into output/page-cache data readable through the file path. This can disclose kernel memory and is not limited to a few fixed bytes.\nI:N - The faulty operation is an out-of-bounds read from the input page mapping followed by copying into the file output page; it does not write out of bounds or corrupt kernel control data. No direct integrity modification primitive is evident.\nA:H - syzbot demonstrated a KASAN slab-out-of-bounds/use-after-free read in this path, and such kernel memory-safety faults can produce an oops/panic on hardened or faulting configurations. The crafted image can retrigger the fault through repeated reads."
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    "redhat_vex": {
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      "cve": "CVE-2026-43166",
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      "title": "kernel: erofs: fix interlaced plain identification for encoded extents",
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      "cve": "CVE-2026-43166",
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}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.