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CVE-2024-49884— ext4: fix slab-use-after-free in ext4_split_extent_at()

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文件系统在ext4_split_extent_at函数中对已释放内存的不当访问，导致释放后重用问题。

CVSS 7.8 · High EPSS 0.28% · P20

Possible ATT&CK Techniques 1 AI

T1068 · Exploitation for Privilege Escalation

Affected Version Matrix 20

VendorProduct Version RangeStatus
Linux Linux dfe5080939ea4686b3414b5d970a9b26733c57a4< 393a46f60ea4f249dc9d496d4eb2d542f5e11ade affected
dfe5080939ea4686b3414b5d970a9b26733c57a4< 448100a29395b0c8b4c42967155849fe0fbe808f affected
dfe5080939ea4686b3414b5d970a9b26733c57a4< e52f933598b781d291b9297e39c463536da0e185 affected
dfe5080939ea4686b3414b5d970a9b26733c57a4< cafcc1bd62934547c76abf46c6d0d54f135006fe affected
dfe5080939ea4686b3414b5d970a9b26733c57a4< a5401d4c3e2a3d25643c567d26e6de327774a2c9 affected
dfe5080939ea4686b3414b5d970a9b26733c57a4< 8fe117790b37c84c651e2bad9efc0e7fda73c0e3 affected
dfe5080939ea4686b3414b5d970a9b26733c57a4< 5d949ea75bb529ea6342e83465938a3b0ac51238 affected
dfe5080939ea4686b3414b5d970a9b26733c57a4< 915ac3630488af0ca194dc63b86d99802b4f6e18 affected
… +12 more rows
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I. Basic Information for CVE-2024-49884

Vulnerability Information
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Vulnerability Title
ext4: fix slab-use-after-free in ext4_split_extent_at()
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: ext4: fix slab-use-after-free in ext4_split_extent_at() We hit the following use-after-free: ================================================================== BUG: KASAN: slab-use-after-free in ext4_split_extent_at+0xba8/0xcc0 Read of size 2 at addr ffff88810548ed08 by task kworker/u20:0/40 CPU: 0 PID: 40 Comm: kworker/u20:0 Not tainted 6.9.0-dirty #724 Call Trace: <TASK> kasan_report+0x93/0xc0 ext4_split_extent_at+0xba8/0xcc0 ext4_split_extent.isra.0+0x18f/0x500 ext4_split_convert_extents+0x275/0x750 ext4_ext_handle_unwritten_extents+0x73e/0x1580 ext4_ext_map_blocks+0xe20/0x2dc0 ext4_map_blocks+0x724/0x1700 ext4_do_writepages+0x12d6/0x2a70 [...] Allocated by task 40: __kmalloc_noprof+0x1ac/0x480 ext4_find_extent+0xf3b/0x1e70 ext4_ext_map_blocks+0x188/0x2dc0 ext4_map_blocks+0x724/0x1700 ext4_do_writepages+0x12d6/0x2a70 [...] Freed by task 40: kfree+0xf1/0x2b0 ext4_find_extent+0xa71/0x1e70 ext4_ext_insert_extent+0xa22/0x3260 ext4_split_extent_at+0x3ef/0xcc0 ext4_split_extent.isra.0+0x18f/0x500 ext4_split_convert_extents+0x275/0x750 ext4_ext_handle_unwritten_extents+0x73e/0x1580 ext4_ext_map_blocks+0xe20/0x2dc0 ext4_map_blocks+0x724/0x1700 ext4_do_writepages+0x12d6/0x2a70 [...] ================================================================== The flow of issue triggering is as follows: ext4_split_extent_at path = *ppath ext4_ext_insert_extent(ppath) ext4_ext_create_new_leaf(ppath) ext4_find_extent(orig_path) path = *orig_path read_extent_tree_block // return -ENOMEM or -EIO ext4_free_ext_path(path) kfree(path) *orig_path = NULL a. If err is -ENOMEM: ext4_ext_dirty(path + path->p_depth) // path use-after-free !!! b. If err is -EIO and we have EXT_DEBUG defined: ext4_ext_show_leaf(path) eh = path[depth].p_hdr // path also use-after-free !!! So when trying to zeroout or fix the extent length, call ext4_find_extent() to update the path. In addition we use *ppath directly as an ext4_ext_show_leaf() input to avoid possible use-after-free when EXT_DEBUG is defined, and to avoid unnecessary path updates.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
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文件系统在ext4_split_extent_at函数中对已释放内存的不当访问，导致释放后重用问题。
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 dfe5080939ea4686b3414b5d970a9b26733c57a4 ~ 393a46f60ea4f249dc9d496d4eb2d542f5e11ade -
Linux Linux 3.18 -

II. Public POCs for CVE-2024-49884

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III. Intelligence Information for CVE-2024-49884

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Patches & Fixes for CVE-2024-49884 (2)

Same Patch Batch · Linux · 2024-10-21 · 372 CVEs total

CVE-2022-48985 9.8 CRITICAL net: mana: Fix race on per-CQ variable napi work_done
CVE-2024-50033 9.8 CRITICAL slip: make slhc_remember() more robust against malicious packets
CVE-2024-49855 9.8 CRITICAL nbd: fix race between timeout and normal completion
CVE-2022-49003 9.8 CRITICAL nvme: fix SRCU protection of nvme_ns_head list
CVE-2024-50043 9.8 CRITICAL nfsd: fix possible badness in FREE_STATEID
CVE-2024-47695 9.8 CRITICAL RDMA/rtrs-clt: Reset cid to con_num - 1 to stay in bounds
CVE-2024-50047 9.8 CRITICAL smb: client: fix UAF in async decryption
CVE-2024-50046 9.8 CRITICAL NFSv4: Prevent NULL-pointer dereference in nfs42_complete_copies()
CVE-2024-49996 9.4 CRITICAL cifs: Fix buffer overflow when parsing NFS reparse points
CVE-2024-47678 9.4 CRITICAL icmp: change the order of rate limits
CVE-2022-49017 8.8 HIGH tipc: re-fetch skb cb after tipc_msg_validate
CVE-2022-49015 8.8 HIGH net: hsr: Fix potential use-after-free
CVE-2024-49950 8.8 HIGH Bluetooth: L2CAP: Fix uaf in l2cap_connect
CVE-2024-49939 8.8 HIGH wifi: rtw89: avoid to add interface to list twice when SER
CVE-2024-50041 8.8 HIGH i40e: Fix macvlan leak by synchronizing access to mac_filter_hash
CVE-2024-49936 8.8 HIGH net/xen-netback: prevent UAF in xenvif_flush_hash()
CVE-2024-50029 8.8 HIGH Bluetooth: hci_conn: Fix UAF in hci_enhanced_setup_sync
CVE-2024-49930 8.8 HIGH wifi: ath11k: fix array out-of-bound access in SoC stats
CVE-2024-49988 8.8 HIGH ksmbd: add refcnt to ksmbd_conn struct
CVE-2024-49982 8.8 HIGH aoe: fix the potential use-after-free problem in more places

Showing top 20 of 372 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

V. Comments for CVE-2024-49884

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