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CVE-2023-53813— ext4: fix rbtree traversal bug in ext4_mb_use_preallocated

Quick assessment

Affected
Linux Linux
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于ext4_mb_use_preallocated未正确处理rbtree遍历，可能导致预分配空间重叠。

AI Predicted 5.5 Difficulty: Moderate EPSS 0.19% · P8

Possible ATT&CK Techniques 1 AI

T1496 · Resource Hijacking

Affected Version Matrix 6

VendorProduct Version RangeStatus
Linux Linux 3872778664e36528caf8b27f355e75482f6d562d< 339fee69a1daa71d6f97e47a867e2c32419a2406 affected
3872778664e36528caf8b27f355e75482f6d562d< 9d3de7ee192a6a253f475197fe4d2e2af10a731f affected
6.4 affected
< 6.4 unaffected
6.4.8≤ 6.4.* unaffected
6.5≤ * unaffected
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I. Basic Information for CVE-2023-53813

Vulnerability Information
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Vulnerability Title
ext4: fix rbtree traversal bug in ext4_mb_use_preallocated
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: ext4: fix rbtree traversal bug in ext4_mb_use_preallocated During allocations, while looking for preallocations(PA) in the per inode rbtree, we can't do a direct traversal of the tree because ext4_mb_discard_group_preallocation() can paralelly mark the pa deleted and that can cause direct traversal to skip some entries. This was leading to a BUG_ON() being hit [1] when we missed a PA that could satisfy our request and ultimately tried to create a new PA that would overlap with the missed one. To makes sure we handle that case while still keeping the performance of the rbtree, we make use of the fact that the only pa that could possibly overlap the original goal start is the one that satisfies the below conditions: 1. It must have it's logical start immediately to the left of (ie less than) original logical start. 2. It must not be deleted To find this pa we use the following traversal method: 1. Descend into the rbtree normally to find the immediate neighboring PA. Here we keep descending irrespective of if the PA is deleted or if it overlaps with our request etc. The goal is to find an immediately adjacent PA. 2. If the found PA is on right of original goal, use rb_prev() to find the left adjacent PA. 3. Check if this PA is deleted and keep moving left with rb_prev() until a non deleted PA is found. 4. This is the PA we are looking for. Now we can check if it can satisfy the original request and proceed accordingly. This approach also takes care of having deleted PAs in the tree. (While we are at it, also fix a possible overflow bug in calculating the end of a PA) [1] https://lore.kernel.org/linux-ext4/CA+G9fYv2FRpLqBZf34ZinR8bU2_ZRAUOjKAD3+tKRFaEQHtt8Q@mail.gmail.com/
Source: CVE Program / CVE List V5
CVSS Information
N/A
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5
Vulnerability Title
Linux kernel 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于ext4_mb_use_preallocated未正确处理rbtree遍历，可能导致预分配空间重叠。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
Linux Linux 3872778664e36528caf8b27f355e75482f6d562d ~ 339fee69a1daa71d6f97e47a867e2c32419a2406 -
Linux Linux 6.4 -

II. Public POCs for CVE-2023-53813

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III. Intelligence Information for CVE-2023-53813

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Same Patch Batch · Linux · 2025-12-09 · 152 CVEs total

CVE-2022-50666 9.8 CRITICAL RDMA/siw: Fix QP destroy to wait for all references dropped.
CVE-2025-40343 9.8 CRITICAL nvmet-fc: avoid scheduling association deletion twice
CVE-2023-53794 9.8 CRITICAL cifs: fix session state check in reconnect to avoid use-after-free issue
CVE-2025-40342 8.8 HIGH nvme-fc: use lock accessing port_state and rport state
CVE-2023-53822 8.8 HIGH wifi: ath11k: Ignore frags from uninitialized peer in dp.
CVE-2023-53785 8.8 HIGH mt76: mt7921: don't assume adequate headroom for SDIO headers
CVE-2025-40336 8.8 HIGH drm/gpusvm: fix hmm_pfn_to_map_order() usage
CVE-2023-53827 8.8 HIGH Bluetooth: L2CAP: Fix use-after-free in l2cap_disconnect_{req,rsp}
CVE-2025-40328 8.8 HIGH smb: client: fix potential UAF in smb2_close_cached_fid()
CVE-2023-53851 8.4 HIGH drm/msm/dp: Drop aux devices together with DP controller
CVE-2025-40337 8.2 HIGH net: stmmac: Correctly handle Rx checksum offload errors
CVE-2022-50656 8.1 HIGH nfc: pn533: Clear nfc_target before being used
CVE-2023-53803 8.1 HIGH scsi: ses: Fix slab-out-of-bounds in ses_enclosure_data_process()
CVE-2023-53800 7.8 HIGH ubi: Fix use-after-free when volume resizing failed
CVE-2023-53860 7.8 HIGH dm: don't attempt to queue IO under RCU protection
CVE-2023-53829 7.8 HIGH f2fs: flush inode if atomic file is aborted
CVE-2023-53790 7.8 HIGH bpf: Zeroing allocated object from slab in bpf memory allocator
CVE-2023-53836 7.8 HIGH bpf, sockmap: Fix skb refcnt race after locking changes
CVE-2023-53810 7.8 HIGH blk-mq: release crypto keyslot before reporting I/O complete
CVE-2023-53846 7.8 HIGH f2fs: fix to do sanity check on direct node in truncate_dnode()

Showing top 20 of 152 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

V. Comments for CVE-2023-53813

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