CVE-2024-47736: Linux kernel · erofs: handle overlapped pclusters out of crafted images properly
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 5.5 Medium · fixed in 6.8.0-1029.31~22.04.1 : update Linux kernel when convenient.
Data as of 28 Oct 2026, 11:13 UTC
- Patch
- Available – fixed in 6.8.0-1029.31~22.04.1, 6.8.0-1029.34~22.04.1, 6.8.0-1030.32~22.04.1 +30
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 21 Oct 2024
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Patches and advisories
- ubuntu.com/security/notices/USN-7276-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7277-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7310-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7513-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7513-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7514-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7515-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7513-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-7522-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7515-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7523-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7524-1 (opens in a new tab)
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 24.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-azure-6.11pkg:deb/ubuntu/linux-azure-6.11?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-azure-nvidiapkg:deb/ubuntu/linux-azure-nvidia?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
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.
References
- ubuntu.com/security/CVE-2024-47736 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2024-47736 (opens in a new tab)
- git.kernel.org/linus/9e2f9d34dd12e6e5b244ec488bcebd0c2d566c50 (opens in a new tab)
- git.kernel.org/stable/c/b9b30af0e86ffb485301ecd83b9129c9dfb7ebf8 (opens in a new tab)
- git.kernel.org/stable/c/9cfa199bcbbbba31cbf97b2786f44f4464f3f29a (opens in a new tab)
- git.kernel.org/stable/c/9e2f9d34dd12e6e5b244ec488bcebd0c2d566c50 (opens in a new tab)
- ubuntu.com/security/notices/USN-7276-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7277-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7310-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7513-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7513-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7514-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7515-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7513-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-7522-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7515-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7523-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7524-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7513-4 (opens in a new tab)
- ubuntu.com/security/notices/USN-7513-5 (opens in a new tab)