ext4: fix double brelse() the buffer of the extents path

MITRE NVD CVE.ORG JSON API Print: PDF PDF

Summary

CVECVE-2024-49882
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2024-10-21 18:15:10 UTC
Updated2026-05-12 19:08:45 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: ext4: fix double brelse() the buffer of the extents path In ext4_ext_try_to_merge_up(), set path[1].p_bh to NULL after it has been released, otherwise it may be released twice. An example of what triggers this is as follows: split2 map split1 |--------|-------|--------| ext4_ext_map_blocks ext4_ext_handle_unwritten_extents ext4_split_convert_extents // path->p_depth == 0 ext4_split_extent // 1. do split1 ext4_split_extent_at |ext4_ext_insert_extent | ext4_ext_create_new_leaf | ext4_ext_grow_indepth | le16_add_cpu(&neh->eh_depth, 1) | ext4_find_extent | // return -ENOMEM |// get error and try zeroout |path = ext4_find_extent | path->p_depth = 1 |ext4_ext_try_to_merge | ext4_ext_try_to_merge_up | path->p_depth = 0 | brelse(path[1].p_bh) ---> not set to NULL here |// zeroout success // 2. update path ext4_find_extent // 3. do split2 ext4_split_extent_at ext4_ext_insert_extent ext4_ext_create_new_leaf ext4_ext_grow_indepth le16_add_cpu(&neh->eh_depth, 1) ext4_find_extent path[0].p_bh = NULL; path->p_depth = 1 read_extent_tree_block ---> return err // path[1].p_bh is still the old value ext4_free_ext_path ext4_ext_drop_refs // path->p_depth == 1 brelse(path[1].p_bh) ---> brelse a buffer twice Finally got the following WARRNING when removing the buffer from lru: ============================================ VFS: brelse: Trying to free free buffer WARNING: CPU: 2 PID: 72 at fs/buffer.c:1241 __brelse+0x58/0x90 CPU: 2 PID: 72 Comm: kworker/u19:1 Not tainted 6.9.0-dirty #716 RIP: 0010:__brelse+0x58/0x90 Call Trace: <TASK> __find_get_block+0x6e7/0x810 bdev_getblk+0x2b/0x480 __ext4_get_inode_loc+0x48a/0x1240 ext4_get_inode_loc+0xb2/0x150 ext4_reserve_inode_write+0xb7/0x230 __ext4_mark_inode_dirty+0x144/0x6a0 ext4_ext_insert_extent+0x9c8/0x3230 ext4_ext_map_blocks+0xf45/0x2dc0 ext4_map_blocks+0x724/0x1700 ext4_do_writepages+0x12d6/0x2a70 [...] ============================================

Risk And Classification

Primary CVSS: v3.1 7.8 HIGH from [email protected]

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Problem Types: CWE-415

CVSS v3.1 Breakdown

Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Operating System Debian Debian Linux 11.0 All All All
Operating System Linux Linux Kernel All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected ecb94f5fdf4b72547fca022421a9dca1672bddd4 d4574bda63906bf69660e001470bfe1a0ac524ae git Not specified
CNA Linux Linux affected ecb94f5fdf4b72547fca022421a9dca1672bddd4 f9fd47c9d9548f9e47fa60098eab99dde175401d git Not specified
CNA Linux Linux affected ecb94f5fdf4b72547fca022421a9dca1672bddd4 b6c29c8f3d7cb67b505f3b2f6c242d52298d1f2e git Not specified
CNA Linux Linux affected ecb94f5fdf4b72547fca022421a9dca1672bddd4 32bbb59e3f18facd7201bef110010bf35819b8c3 git Not specified
CNA Linux Linux affected ecb94f5fdf4b72547fca022421a9dca1672bddd4 78bbc3d15b6f443acb26e94418c445bac940d414 git Not specified
CNA Linux Linux affected ecb94f5fdf4b72547fca022421a9dca1672bddd4 68a69cf60660c73990c1875f94a5551600b04775 git Not specified
CNA Linux Linux affected ecb94f5fdf4b72547fca022421a9dca1672bddd4 7633407ca4ab8be2916ab214eb44ccebc6a50e1a git Not specified
CNA Linux Linux affected ecb94f5fdf4b72547fca022421a9dca1672bddd4 230ee0535d01478bad9a3037292043f39b9be10b git Not specified
CNA Linux Linux affected ecb94f5fdf4b72547fca022421a9dca1672bddd4 dcaa6c31134c0f515600111c38ed7750003e1b9c git Not specified
CNA Linux Linux affected 3.7 Not specified
CNA Linux Linux unaffected 3.7 semver Not specified
CNA Linux Linux unaffected 4.19.323 4.19.* semver Not specified
CNA Linux Linux unaffected 5.4.285 5.4.* semver Not specified
CNA Linux Linux unaffected 5.10.227 5.10.* semver Not specified
CNA Linux Linux unaffected 5.15.168 5.15.* semver Not specified
CNA Linux Linux unaffected 6.1.113 6.1.* semver Not specified
CNA Linux Linux unaffected 6.6.55 6.6.* semver Not specified
CNA Linux Linux unaffected 6.10.14 6.10.* semver Not specified
CNA Linux Linux unaffected 6.11.3 6.11.* semver Not specified
CNA Linux Linux unaffected 6.12 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
lists.debian.org/debian-lts-announce/2025/03/msg00002.html af854a3a-2127-422b-91ae-364da2661108 lists.debian.org Mailing List, Third Party Advisory
git.kernel.org/stable/c/7633407ca4ab8be2916ab214eb44ccebc6a50e1a 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/68a69cf60660c73990c1875f94a5551600b04775 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/b6c29c8f3d7cb67b505f3b2f6c242d52298d1f2e 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/d4574bda63906bf69660e001470bfe1a0ac524ae 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/78bbc3d15b6f443acb26e94418c445bac940d414 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/f9fd47c9d9548f9e47fa60098eab99dde175401d 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/230ee0535d01478bad9a3037292043f39b9be10b 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/32bbb59e3f18facd7201bef110010bf35819b8c3 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
lists.debian.org/debian-lts-announce/2025/01/msg00001.html af854a3a-2127-422b-91ae-364da2661108 lists.debian.org Mailing List, Third Party Advisory
git.kernel.org/stable/c/dcaa6c31134c0f515600111c38ed7750003e1b9c 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis
© CVE.report 2026 |

Use of this information constitutes acceptance for use in an AS IS condition. There are NO warranties, implied or otherwise, with regard to this information or its use. Any use of this information is at the user's risk. It is the responsibility of user to evaluate the accuracy, completeness or usefulness of any information, opinion, advice or other content. EACH USER WILL BE SOLELY RESPONSIBLE FOR ANY consequences of his or her direct or indirect use of this web site. ALL WARRANTIES OF ANY KIND ARE EXPRESSLY DISCLAIMED. This site will NOT BE LIABLE FOR ANY DIRECT, INDIRECT or any other kind of loss.

CVE, CWE, and OVAL are registred trademarks of The MITRE Corporation and the authoritative source of CVE content is MITRE's CVE web site. This site includes MITRE data granted under the following license.

Free CVE JSON API cve.report/api

CVE.report and Source URL Uptime Status status.cve.report