CVE-2024-47736

Advisory lineage Upstream: 0 Downstream: 16
Modified
Published: 21 Oct 2024, 12:14
Last modified:11 May 2026, 20:39

Vulnerability Summary

Overall Risk (default)
low
22/100
CVSS Score
5.5 MEDIUM
v3.1 (nvd)
EPSS Score
<0.01% LOW
0% probability 0.00%
KEV
Not listed
Ransomware
No reports
Public exploits
None found
Dark Web
Not detected

Timeline

21 Oct 2024, 12:14
Published
Vulnerability first disclosed
11 May 2026, 20:39
Last Modified
Vulnerability information updated

Description

In the Linux kernel, the following vulnerability has been resolved: erofs: handle overlapped pclusters out of crafted images properly syzbot reported a task hang issue due to a deadlock case where it is waiting for the folio lock of a cached folio that will be used for cache I/Os. After looking into the crafted fuzzed image, I found it's formed with several overlapped big pclusters as below: Ext: logical offset | length : physical offset | length 0: 0.. 16384 | 16384 : 151552.. 167936 | 16384 1: 16384.. 32768 | 16384 : 155648.. 172032 | 16384 2: 32768.. 49152 | 16384 : 537223168.. 537239552 | 16384 ... Here, extent 0/1 are physically overlapped although it's entirely _impossible_ for normal filesystem images generated by mkfs. First, managed folios containing compressed data will be marked as up-to-date and then unlocked immediately (unlike in-place folios) when compressed I/Os are complete. If physical blocks are not submitted in the incremental order, there should be separate BIOs to avoid dependency issues. However, the current code mis-arranges z_erofs_fill_bio_vec() and BIO submission which causes unexpected BIO waits. Second, managed folios will be connected to their own pclusters for efficient inter-queries. However, this is somewhat hard to implement easily if overlapped big pclusters exist. Again, these only appear in fuzzed images so let's simply fall back to temporary short-lived pages for correctness. Additionally, it justifies that referenced managed folios cannot be truncated for now and reverts part of commit 2080ca1ed3e4 ("erofs: tidy up `struct z_erofs_bvec`") for simplicity although it shouldn't be any difference.

CVSS Metrics

  • v3.1•MEDIUM•Score: 5.5CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

EPSS Trends

Current EPSS score: 0.01%• Percentile: 1%

Techniques & Countermeasures

  • CWE-667•Improper Locking

    The product does not properly acquire or release a lock on a resource, leading to unexpected resource state changes and behaviors.

Affected Systems

  • linux•linux

    ≥ 8e6c8fa9f2e95c88a642521a5da19a8e31748846, < c1172e65aad4b115392ea4c6e61e56e5b9b69df4 | ≥ 8e6c8fa9f2e95c88a642521a5da19a8e31748846, < 1bf7e414cac303c9aec1be67872e19be8b64980c | ≥ 8e6c8fa9f2e95c88a642521a5da19a8e31748846, < b9b30af0e86ffb485301ecd83b9129c9dfb7ebf8 | ≥ 8e6c8fa9f2e95c88a642521a5da19a8e31748846, < 9cfa199bcbbbba31cbf97b2786f44f4464f3f29a | ≥ 8e6c8fa9f2e95c88a642521a5da19a8e31748846, < 9e2f9d34dd12e6e5b244ec488bcebd0c2d566c50 | 5.13

  • linux•linux_kernel

    ≥ 5.13, < 6.10.13 | ≥ 6.11, < 6.11.2

References (5)