NVD / CVE Program· CNA Linux

CVE-2024-53171: ubifs: authentication: Fix use-after-free in ubifs_tnc_end_commit

Noroxi assessment

Priority: Monitor (action score 31/100)

The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
Probability of exploitation in the next 30 days: 0.32% (FIRST EPSS).
Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
Fixed version: Linux Linux 01d3a2293d7e4edfff96618c15727db7e51f11b6, 2497479aecebe869d23a0064e0fd1a03e34f0e2a, 398a91599d263e41c5f95a2fd4ebdb6280b5c6c3; azl3 kernel 6.6.57.1-7 on Azure Linux 3.0 6.6.64.2-1; cbl2 kernel 5.15.173.1-2 on CBL Mariner 2.0 5.15.176.3-1.

Low priority for now. Upgrade to Linux Linux 01d3a2293d7e4edfff96618c15727db7e51f11b6, 2497479aecebe869d23a0064e0fd1a03e34f0e2a, 398a91599d263e41c5f95a2fd4ebdb6280b5c6c3; azl3 kernel 6.6.57.1-7 on Azure Linux 3.0 6.6.64.2-1; cbl2 kernel 5.15.173.1-2 on CBL Mariner 2.0 5.15.176.3-1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

In the Linux kernel, the following vulnerability has been resolved: ubifs: authentication: Fix use-after-free in ubifs_tnc_end_commit After an insertion in TNC, the tree might split and cause a node to change its `znode->parent`. A further deletion of other nodes in the tree (which also could free the nodes), the aforementioned node's `znode->cparent` could still point to a freed node. This `znode->cparent` may not be updated when getting nodes to commit in `ubifs_tnc_start_commit()`. This could then trigger a use-after-free when accessing the `znode->cparent` in `write_index()` in `ubifs_tnc_end_commit()`. This can be triggered by running rm -f /etc/test-file.bin dd if=/dev/urandom of=/etc/test-file.bin bs=1M count=60 conv=fsync in a loop, and with `CONFIG_UBIFS_FS_AUTHENTICATION`. KASAN then reports: BUG: KASAN: use-after-free in ubifs_tnc_end_commit+0xa5c/0x1950 Write of size 32 at addr ffffff800a3af86c by task ubifs_bgt0_20/153 Call trace: dump_backtrace+0x0/0x340 show_stack+0x18/0x24 dump_stack_lvl+0x9c/0xbc print_address_description.constprop.0+0x74/0x2b0 kasan_report+0x1d8/0x1f0 kasan_check_range+0xf8/0x1a0 memcpy+0x84/0xf4 ubifs_tnc_end_commit+0xa5c/0x1950 do_commit+0x4e0/0x1340 ubifs_bg_thread+0x234/0x2e0 kthread+0x36c/0x410 ret_from_fork+0x10/0x20 Allocated by task 401: kasan_save_stack+0x38/0x70 __kasan_kmalloc+0x8c/0xd0 __kmalloc+0x34c/0x5bc tnc_insert+0x140/0x16a4 ubifs_tnc_add+0x370/0x52c ubifs_jnl_write_data+0x5d8/0x870 do_writepage+0x36c/0x510 ubifs_writepage+0x190/0x4dc __writepage+0x58/0x154 write_cache_pages+0x394/0x830 do_writepages+0x1f0/0x5b0 filemap_fdatawrite_wbc+0x170/0x25c file_write_and_wait_range+0x140/0x190 ubifs_fsync+0xe8/0x290 vfs_fsync_range+0xc0/0x1e4 do_fsync+0x40/0x90 __arm64_sys_fsync+0x34/0x50 invoke_syscall.constprop.0+0xa8/0x260 do_el0_svc+0xc8/0x1f0 el0_svc+0x34/0x70 el0t_64_sync_handler+0x108/0x114 el0t_64_sync+0x1a4/0x1a8 Freed by task 403: kasan_save_stack+0x38/0x70 kasan_set_track+0x28/0x40 kasan_set_free_info+0x28/0x4c __kasan_slab_free+0xd4/0x13c kfree+0xc4/0x3a0 tnc_delete+0x3f4/0xe40 ubifs_tnc_remove_range+0x368/0x73c ubifs_tnc_remove_ino+0x29c/0x2e0 ubifs_jnl_delete_inode+0x150/0x260 ubifs_evict_inode+0x1d4/0x2e4 evict+0x1c8/0x450 iput+0x2a0/0x3c4 do_unlinkat+0x2cc/0x490 __arm64_sys_unlinkat+0x90/0x100 invoke_syscall.constprop.0+0xa8/0x260 do_el0_svc+0xc8/0x1f0 el0_svc+0x34/0x70 el0t_64_sync_handler+0x108/0x114 el0t_64_sync+0x1a4/0x1a8 The offending `memcpy()` in `ubifs_copy_hash()` has a use-after-free when a node becomes root in TNC but still has a `cparent` to an already freed node. More specifically, consider the following TNC: zroot / / zp1 / / zn Inserting a new node `zn_new` with a key smaller then `zn` will trigger a split in `tnc_insert()` if `zp1` is full: zroot / \ / \ zp1 zp2 / \ / \ zn_new zn `zn->parent` has now been moved to `zp2`, *but* `zn->cparent` still points to `zp1`. Now, consider a removal of all the nodes _except_ `zn`. Just when `tnc_delete()` is about to delete `zroot` and `zp2`: zroot \ \ zp2 \ \ zn `zroot` and `zp2` get freed and the tree collapses: zn `zn` now becomes the new `zroot`. `get_znodes_to_commit()` will now only find `zn`, the new `zroot`, and `write_index()` will check its `znode->cparent` that wrongly points to the already freed `zp1`. `ubifs_copy_hash()` thus gets wrongly called with `znode->cparent->zbranch[znode->iip].hash` that triggers the use-after-free! Fix this by explicitly setting `znode->cparent` to `NULL` in `get_znodes_to_commit()` for the root node. The search for the dirty nodes ---truncated---

HighCVSS 7.8 · v3.1—No exploit Fix available

Memory safety

BDU:2025-04991

Published: Dec 27, 2024
Updated: Aug 5, 2026
EPSS: 0.3% · 25th percentile
CWE: CWE-416

Report tools

JSON

Action score

Monitor

Low priority for now.

CVSS: 31 / 40 · 7.8 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 0.3%

CISA SSVC decision

Exploitation: none
Automatable: no
Technical impact: total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD: 7.8
CNA · Linux: 7.8; agree

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

Not in KEV: no record of exploitation in the wild
No public exploit code on record
A fix has been released

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

Vendor	Product	CPE
linux	linux kernel	cpe:2.3:o:linux:linux_kernel

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

linux linux kernel4.20 and later · before 5.4.287
linux linux kernel5.5 and later · before 5.10.231
linux linux kernel5.11 and later · before 5.15.174
linux linux kernel5.16 and later · before 6.1.120
linux linux kernel6.2 and later · before 6.6.64
linux linux kernel6.7 and later · before 6.11.11
linux linux kernel6.12 and later · before 6.12.2

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

Linux Linux
- 4.20affected
- 16a26b20d2afd0cf063816725b45b12e78d5bb31 and later · before daac4aa1825de0dbc1a6eede2fa7f9fc53f14223affected · git
- 16a26b20d2afd0cf063816725b45b12e78d5bb31 and later · before 8d8b3f5f4cbfbf6cb0ea4a4d5dc296872b4151ebaffected · git
- 16a26b20d2afd0cf063816725b45b12e78d5bb31 and later · before 4d9807048b851d7a58d5bd089c16254af896e4dfaffected · git
- 16a26b20d2afd0cf063816725b45b12e78d5bb31 and later · before 74981f7577d183acad1cd58f74c10d263711a215affected · git
- 16a26b20d2afd0cf063816725b45b12e78d5bb31 and later · before 01d3a2293d7e4edfff96618c15727db7e51f11b6affected · git
- 16a26b20d2afd0cf063816725b45b12e78d5bb31 and later · before 398a91599d263e41c5f95a2fd4ebdb6280b5c6c3affected · git
- 16a26b20d2afd0cf063816725b45b12e78d5bb31 and later · before 2497479aecebe869d23a0064e0fd1a03e34f0e2aaffected · git
- 16a26b20d2afd0cf063816725b45b12e78d5bb31 and later · before 4617fb8fc15effe8eda4dd898d4e33eb537a7140affected · git
- before 4.20not affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

Ecosystem	Package	Affected range	Fix
Debian:12	linux	before 6.1.123-1	6.1.123-1
Debian:13	linux	before 6.12.3-1	6.12.3-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

CVE-2026-31431crypto: algif_aead - Revert to operating out-of-placeKEV
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CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe KEV
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CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
85Now

Published before and after this one in the same product

← EarlierCVE-2022-49034Dec 27, 2024 · sh: cpuinfo: Fix a warning for CONFIG_CPUMASK_OFFSTACK
22Monitor
← EarlierCVE-2024-53169Dec 27, 2024 · nvme-fabrics: fix kernel crash while shutting down controller
18Monitor
Later →CVE-2024-53173Dec 27, 2024 · NFSv4.0: Fix a use-after-free problem in the asynchronous open()
31Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / package	Fixed version	Source
Linux Linux	01d3a2293d7e4edfff96618c15727db7e51f11b6	Vendor (CNA)
Linux Linux	2497479aecebe869d23a0064e0fd1a03e34f0e2a	Vendor (CNA)
Linux Linux	398a91599d263e41c5f95a2fd4ebdb6280b5c6c3	Vendor (CNA)
Linux Linux	4617fb8fc15effe8eda4dd898d4e33eb537a7140	Vendor (CNA)
Linux Linux	4d9807048b851d7a58d5bd089c16254af896e4df	Vendor (CNA)
Linux Linux	74981f7577d183acad1cd58f74c10d263711a215	Vendor (CNA)
Linux Linux	8d8b3f5f4cbfbf6cb0ea4a4d5dc296872b4151eb	Vendor (CNA)
Linux Linux	daac4aa1825de0dbc1a6eede2fa7f9fc53f14223	Vendor (CNA)
azl3 kernel 6.6.57.1-7 on Azure Linux 3.0	6.6.64.2-1 · CBL-Mariner Releases	Microsoft (MSRC)
cbl2 kernel 5.15.173.1-2 on CBL Mariner 2.0	5.15.176.3-1 · CBL-Mariner Releases	Microsoft (MSRC)
debian:linux	6.1.123-1 · Debian:12	Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

Someone with local access to the system can trigger it.
A low-privileged account is enough.
No user action is required.
No special conditions are required; it is repeatable.

If successful

Confidentiality: high · data can be read
Integrity: high · data or configuration can be modified
Availability: high · the service can be disrupted

Attack vector: Local
Attack complexity: Low
Privileges required: Low
User interaction: None
Scope: Unchanged
Confidentiality impact: High
Integrity impact: High
Availability impact: High

Weakness class (CWE)

CWE-416 · Use After Free

CVSS vector

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

nvd-primary

Root cause

After a memory region is freed, another reference pointing to it is still used. By then, the same region may have been allocated for different data.

The bug in code

The whole CWE-416 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

1free(dev->buf);
2/* ... another thread is still running ... */
3process(dev->buf);

Fixed

1lock(&dev->lock);
2free(dev->buf);
3dev->buf = NULL;
4unlock(&dev->lock);

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

Fix✗ → ✓Sep 28, 2026, 10:11 PM UTC

For records you follow, these changes also arrive as notifications. →

References

git.kernel.org/stable/c/01d3a2293d7e4edfff96618c15727db7e51f11b6

Show all references (9 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records