NVD / CVE Program· CNA Linux

CVE-2024-39496: btrfs: zoned: fix use-after-free due to race with dev replace

HighCVSS 7.8 · v3.1—No exploit Fix available

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: 0.28% (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 0090d6e1b210551e63cf43958dc7a1ec942cdde9, 092571ef9a812566c8f2c9038d9c2a64c49788d6, 17765964703b88d8befd899f8501150bb7e07e43; azl3 kernel 6.6.22.1-2 on Azure Linux 3.0 6.6.35.1-5; azl3 kernel 6.6.35.1-5 on Azure Linux 3.0 -.
Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 0090d6e1b210551e63cf43958dc7a1ec942cdde9, 092571ef9a812566c8f2c9038d9c2a64c49788d6, 17765964703b88d8befd899f8501150bb7e07e43; azl3 kernel 6.6.22.1-2 on Azure Linux 3.0 6.6.35.1-5; azl3 kernel 6.6.35.1-5 on Azure Linux 3.0 - 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: btrfs: zoned: fix use-after-free due to race with dev replace While loading a zone's info during creation of a block group, we can race with a device replace operation and then trigger a use-after-free on the device that was just replaced (source device of the replace operation). This happens because at btrfs_load_zone_info() we extract a device from the chunk map into a local variable and then use the device while not under the protection of the device replace rwsem. So if there's a device replace operation happening when we extract the device and that device is the source of the replace operation, we will trigger a use-after-free if before we finish using the device the replace operation finishes and frees the device. Fix this by enlarging the critical section under the protection of the device replace rwsem so that all uses of the device are done inside the critical section.

Memory safety

Published: Jul 12, 2024
Updated: Aug 5, 2026
EPSS: 0.2% · 21th 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 · 0.2%

CISA SSVC decision

Exploitation: none
Automatable: no
Technical impact: partial

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

If any of these changes, we'll tell you in the daily email digest.

Is your version affected? Check it

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
debian	debian linux	cpe:2.3:o:debian:debian_linux

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
- 5.11affected
- 5b316468983dfa9473ff0f1c42e4e30b4c267141 and later · before 17765964703b88d8befd899f8501150bb7e07e43affected · git
- 5b316468983dfa9473ff0f1c42e4e30b4c267141 and later · before 092571ef9a812566c8f2c9038d9c2a64c49788d6affected · git
- 5b316468983dfa9473ff0f1c42e4e30b4c267141 and later · before a0cc006f4214b87e70983c692e05bb36c59b5752affected · git
- 5b316468983dfa9473ff0f1c42e4e30b4c267141 and later · before 0090d6e1b210551e63cf43958dc7a1ec942cdde9affected · git
- before 5.11not affected · semver
- 6.1.95 and later · up to and including 6.1.*not affected · semver
- 6.6.35 and later · up to and including 6.6.*not affected · semver
- 6.9.6 and later · up to and including 6.9.*not affected · semver
- 6.10 and laternot affected · original_commit_for_fix

Affected versions · NVD (4)

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

debian debian linux11.0
linux linux kernel5.12 and later · before 6.1.95
linux linux kernel6.2 and later · before 6.6.35
linux linux kernel6.7 and later · before 6.9.6

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 6.1.99-1	6.1.99-1
Debian:13	linux	before 6.9.7-1	6.9.7-1

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
90Now
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
89Now
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-2024-39494Jul 12, 2024 · ima: Fix use-after-free on a dentry's dname.name
31Monitor
← EarlierCVE-2024-39495Jul 12, 2024 · greybus: Fix use-after-free bug in gb_interface_release due to race condition.
31Monitor
Later →CVE-2024-39497Jul 12, 2024 · drm/shmem-helper: Fix BUG_ON() on mmap(PROT_WRITE, MAP_PRIVATE)
22Monitor

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	0090d6e1b210551e63cf43958dc7a1ec942cdde9	Vendor (CNA)
Linux Linux	092571ef9a812566c8f2c9038d9c2a64c49788d6	Vendor (CNA)
Linux Linux	17765964703b88d8befd899f8501150bb7e07e43	Vendor (CNA)
Linux Linux	a0cc006f4214b87e70983c692e05bb36c59b5752	Vendor (CNA)
azl3 kernel 6.6.22.1-2 on Azure Linux 3.0	6.6.35.1-5 · CBL-Mariner Releases	Microsoft (MSRC)
azl3 kernel 6.6.35.1-5 on Azure Linux 3.0	- · CBL-Mariner Releases	Microsoft (MSRC)
debian:linux	6.1.99-1 · 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.

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

TR-24-0942 · Jul 16, 2024(Linux Kernel Güncellemesi)

All national notices →

Not on record for this CVE: EPSS history · patch commit or PR link · researcher credit · variant or chain candidate · public bounty program.

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 (1)

Fix✗ → ✓Sep 28, 2026, 10:09 PM UTC

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

References

git.kernel.org/stable/c/0090d6e1b210551e63cf43958dc7a1ec942cdde9

Show all references (4 more)

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

All records