CVE-2024-49884ext4: fix slab-use-after-free in ext4_split_extent_at()
Updated under an hour ago ()
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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.
- CVSS
- 7.8 HIGH (v3.1, CNA)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Weakness (CWE)
- Not given
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Linux
- NVD analysis
- Modified
- Record last updated
- Oct 15, 2026
- First seen by InfoSec Signals
- Oct 15, 2026
Affected products
Linux Linux linux:linux (from the name) | from dfe5080939ea4686b3414b5d970a9b26733c57a4 before 393a46f60ea4f249dc9d496d4eb2d542f5e11ade; from dfe5080939ea4686b3414b5d970a9b26733c57a4 before 448100a29395b0c8b4c42967155849fe0fbe808f; from dfe5080939ea4686b3414b5d970a9b26733c57a4 before e52f933598b781d291b9297e39c463536da0e185; from dfe5080939ea4686b3414b5d970a9b26733c57a4 before cafcc1bd62934547c76abf46c6d0d54f135006fe; from dfe5080939ea4686b3414b5d970a9b26733c57a4 before a5401d4c3e2a3d25643c567d26e6de327774a2c9; from dfe5080939ea4686b3414b5d970a9b26733c57a4 before 8fe117790b37c84c651e2bad9efc0e7fda73c0e3; from dfe5080939ea4686b3414b5d970a9b26733c57a4 before 5d949ea75bb529ea6342e83465938a3b0ac51238; from dfe5080939ea4686b3414b5d970a9b26733c57a4 before 915ac3630488af0ca194dc63b86d99802b4f6e18; and 1 more ranges | CNA record |
Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP siemens:simatic_s7_1500_cpu_1518_4_pn_dp_mfp (from the name) | from V3.1.0 before V3.1.5 | CISA ADP |
Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP siemens:simatic_s7_1500_cpu_1518f_4_pn_dp_mfp (from the name) | from V3.1.0 before V3.1.5 | CISA ADP |
Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP siemens:siplus_s7_1500_cpu_1518_4_pn_dp_mfp (from the name) | from V3.1.0 before V3.1.5 | CISA ADP |
Siemens RUGGEDCOM RST2428P siemens:ruggedcom_rst2428p (from the name) | before V3.2 | CISA ADP |
Siemens SCALANCE XC-300/XR-300/XC-400/XR-500WG/XR-500 family siemens:scalance_xc_300_xr_300_xc_400_xr_500wg_xr_500_family (from the name) | before V3.2 | CISA ADP |
Siemens SCALANCE XCM-/XRM-/XCH-/XRH-300 family siemens:scalance_xcm_xrm_xch_xrh_300_family (from the name) | before V3.2 | CISA ADP |
debian debian_linux debian:debian_linux | 11.0 | NVD |
linux linux_kernel linux:linux_kernel | from 3.18 before 4.19.323; from 4.20 before 5.4.290; from 5.5 before 5.10.227; from 5.11 before 5.15.168; from 5.16 before 6.1.113; from 6.2 before 6.6.55; from 6.7 before 6.10.14; from 6.11 before 6.11.3 | NVD |
References
- https://git.kernel.org/stable/c/393a46f60ea4f249dc9d496d4eb2d542f5e11adepatch
- https://git.kernel.org/stable/c/448100a29395b0c8b4c42967155849fe0fbe808fpatch
- https://git.kernel.org/stable/c/e52f933598b781d291b9297e39c463536da0e185patch
- https://git.kernel.org/stable/c/cafcc1bd62934547c76abf46c6d0d54f135006fepatch
- https://git.kernel.org/stable/c/a5401d4c3e2a3d25643c567d26e6de327774a2c9patch
- https://git.kernel.org/stable/c/8fe117790b37c84c651e2bad9efc0e7fda73c0e3patch
- https://git.kernel.org/stable/c/5d949ea75bb529ea6342e83465938a3b0ac51238patch
- https://git.kernel.org/stable/c/915ac3630488af0ca194dc63b86d99802b4f6e18patch
- https://git.kernel.org/stable/c/c26ab35702f8cd0cdc78f96aa5856bfb77be798fpatch
- https://lists.debian.org/debian-lts-announce/2025/01/msg00001.htmlbroken-link
- https://lists.debian.org/debian-lts-announce/2025/03/msg00002.htmlmailing-list, third-party-advisory
- https://cert-portal.siemens.com/productcert/html/ssa-355557.html
- https://cert-portal.siemens.com/productcert/html/ssa-398330.html
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.