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NVD / CVE Program· CNA Linux

CVE-2025-40209: btrfs: fix memory leak of qgroup_list in btrfs_add_qgroup_relation

Noroxi assessment

Priority: Monitor (action score 0/100)

  • 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: 0.19% (FIRST EPSS).
  • Fixed version: Linux Linux 3412d0e973e8f8381747d69033eda809a57a2581, a4d9ebe23bcb79d9d057e3c995db73b7b3aae414, f260c6aff0b8af236084012d14f9f1bf792ea883.

Low priority for now. Upgrade to Linux Linux 3412d0e973e8f8381747d69033eda809a57a2581, a4d9ebe23bcb79d9d057e3c995db73b7b3aae414, f260c6aff0b8af236084012d14f9f1bf792ea883 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: fix memory leak of qgroup_list in btrfs_add_qgroup_relation When btrfs_add_qgroup_relation() is called with invalid qgroup levels (src >= dst), the function returns -EINVAL directly without freeing the preallocated qgroup_list structure passed by the caller. This causes a memory leak because the caller unconditionally sets the pointer to NULL after the call, preventing any cleanup. The issue occurs because the level validation check happens before the mutex is acquired and before any error handling path that would free the prealloc pointer. On this early return, the cleanup code at the 'out' label (which includes kfree(prealloc)) is never reached. In btrfs_ioctl_qgroup_assign(), the code pattern is: prealloc = kzalloc(sizeof(*prealloc), GFP_KERNEL); ret = btrfs_add_qgroup_relation(trans, sa->src, sa->dst, prealloc); prealloc = NULL; // Always set to NULL regardless of return value ... kfree(prealloc); // This becomes kfree(NULL), does nothing When the level check fails, 'prealloc' is never freed by either the callee or the caller, resulting in a 64-byte memory leak per failed operation. This can be triggered repeatedly by an unprivileged user with access to a writable btrfs mount, potentially exhausting kernel memory. Fix this by freeing prealloc before the early return, ensuring prealloc is always freed on all error paths.

—No exploit Fix available
Published
Nov 21, 2025
Updated
Oct 19, 2026
EPSS
0.1% · 9th percentile
CWE
—

Report tools

JSON

Action score

0

Monitor

Low priority for now.

CVSS
0 / 40 · —
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

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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.

—

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

    • 6.11affected
    • 4addc1ffd67ad34394674dc91379dc04cfdd2537 and later · before 3412d0e973e8f8381747d69033eda809a57a2581affected · git
    • 4addc1ffd67ad34394674dc91379dc04cfdd2537 and later · before a4d9ebe23bcb79d9d057e3c995db73b7b3aae414affected · git
    • 4addc1ffd67ad34394674dc91379dc04cfdd2537 and later · before f260c6aff0b8af236084012d14f9f1bf792ea883affected · git
    • before 6.11not affected · semver
    • 6.12.58 and later · up to and including 6.12.*not affected · semver
    • 6.17.8 and later · up to and including 6.17.*not affected · semver
    • 6.18 and laternot affected · original_commit_for_fix

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:13linuxbefore 6.12.63-16.12.63-1
Debian:14linuxbefore 6.17.8-16.17.8-1
openSUSE:Leap 16.0dtb-aarch64before 6.12.0-160000.9.16.12.0-160000.9.1
openSUSE:Leap 16.0kernel-64kbbefore 6.12.0-160000.9.16.12.0-160000.9.1
openSUSE:Leap 16.0kernel-azurebefore 6.12.0-160000.9.16.12.0-160000.9.1
openSUSE:Leap 16.0kernel-defaultbefore 6.12.0-160000.9.16.12.0-160000.9.1
openSUSE:Leap 16.0kernel-default-basebefore 6.12.0-160000.9.1.160000.2.66.12.0-160000.9.1.160000.2.6
openSUSE:Leap 16.0kernel-docsbefore 6.12.0-160000.9.16.12.0-160000.9.1
openSUSE:Leap 16.0kernel-kvmsmallbefore 6.12.0-160000.9.16.12.0-160000.9.1
openSUSE:Leap 16.0kernel-obs-buildbefore 6.12.0-160000.9.16.12.0-160000.9.1
openSUSE:Leap 16.0kernel-obs-qabefore 6.12.0-160000.9.16.12.0-160000.9.1
openSUSE:Leap 16.0kernel-rtbefore 6.12.0-160000.9.16.12.0-160000.9.1
openSUSE:Leap 16.0kernel-sourcebefore 6.12.0-160000.9.16.12.0-160000.9.1
openSUSE:Leap 16.0kernel-symsbefore 6.12.0-160000.9.16.12.0-160000.9.1
openSUSE:Leap 16.0kernel-zfcpdumpbefore 6.12.0-160000.9.16.12.0-160000.9.1
SUSE:Linux Enterprise Server 16.0kernel-azurebefore 6.12.0-160000.9.16.12.0-160000.9.1
SUSE:Linux Enterprise Server 16.0kernel-docsbefore 6.12.0-160000.9.16.12.0-160000.9.1
SUSE:Linux Enterprise Server 16.0kernel-kvmsmallbefore 6.12.0-160000.9.16.12.0-160000.9.1
SUSE:Linux Enterprise Server 16.0kernel-obs-qabefore 6.12.0-160000.9.16.12.0-160000.9.1
SUSE:Linux Enterprise Server 16.0kernel-symsbefore 6.12.0-160000.9.16.12.0-160000.9.1
SUSE:Linux Enterprise Server 16.0kernel-zfcpdumpbefore 6.12.0-160000.9.16.12.0-160000.9.1
SUSE:Linux Micro 6.2kernel-64kbbefore 6.12.0-160000.9.16.12.0-160000.9.1
SUSE:Linux Micro 6.2kernel-defaultbefore 6.12.0-160000.9.16.12.0-160000.9.1
SUSE:Linux Micro 6.2kernel-default-basebefore 6.12.0-160000.9.1.160000.2.66.12.0-160000.9.1.160000.2.6

+3

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-74705udp: fix potential use-after-free in tunnel segmentation
    40Plan
  • CVE-2026-74612veth: fix skb length accounting after XDP frag adjustment
    40Plan
  • CVE-2026-74475vxlan: use neigh_ha_snapshot() in route_shortcircuit()
    40Plan

Published before and after this one in the same product

  • ← EarlierCVE-2025-40207Nov 12, 2025 · media: v4l2-subdev: Fix alloc failure check in v4l2_subdev_call_state_try()
    0Monitor
  • ← EarlierCVE-2025-40208Nov 12, 2025 · media: iris: fix module removal if firmware download failed
    0Monitor
  • Later →CVE-2025-40210Nov 21, 2025 · Revert "NFSD: Remove the cap on number of operations per NFSv4 COMPOUND"
    30Monitor

Remediation

Which version to upgrade to

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

Product / packageFixed versionSource
Linux Linux3412d0e973e8f8381747d69033eda809a57a2581Vendor (CNA)
Linux Linuxa4d9ebe23bcb79d9d057e3c995db73b7b3aae414Vendor (CNA)
Linux Linuxf260c6aff0b8af236084012d14f9f1bf792ea883Vendor (CNA)
debian:linux6.12.63-1 · Debian:13Package registry (OSV)
opensuse:dtb-aarch646.12.0-160000.9.1 · openSUSE:Leap 16.0Package registry (OSV)
opensuse:kernel-64kb6.12.0-160000.9.1 · openSUSE:Leap 16.0Package registry (OSV)
opensuse:kernel-azure6.12.0-160000.9.1 · openSUSE:Leap 16.0Package registry (OSV)
opensuse:kernel-default6.12.0-160000.9.1 · openSUSE:Leap 16.0Package registry (OSV)
opensuse:kernel-default-base6.12.0-160000.9.1.160000.2.6 · openSUSE:Leap 16.0Package registry (OSV)
opensuse:kernel-docs6.12.0-160000.9.1 · openSUSE:Leap 16.0Package registry (OSV)
opensuse:kernel-kvmsmall6.12.0-160000.9.1 · openSUSE:Leap 16.0Package registry (OSV)
opensuse:kernel-obs-build6.12.0-160000.9.1 · openSUSE:Leap 16.0Package registry (OSV)
opensuse:kernel-obs-qa6.12.0-160000.9.1 · openSUSE:Leap 16.0Package registry (OSV)
opensuse:kernel-rt6.12.0-160000.9.1 · openSUSE:Leap 16.0Package registry (OSV)
opensuse:kernel-source6.12.0-160000.9.1 · openSUSE:Leap 16.0Package registry (OSV)
opensuse:kernel-syms6.12.0-160000.9.1 · openSUSE:Leap 16.0Package registry (OSV)
suse:kernel-64kb6.12.0-160000.9.1 · SUSE:Linux Micro 6.2Package registry (OSV)
suse:kernel-azure6.12.0-160000.9.1 · SUSE:Linux Enterprise Server 16.0Package registry (OSV)
suse:kernel-default6.12.0-160000.9.1 · SUSE:Linux Micro 6.2Package registry (OSV)
suse:kernel-default-base6.12.0-160000.9.1.160000.2.6 · SUSE:Linux Micro 6.2Package registry (OSV)
suse:kernel-docs6.12.0-160000.9.1 · SUSE:Linux Enterprise Server 16.0Package registry (OSV)
suse:kernel-kvmsmall6.12.0-160000.9.1 · SUSE:Linux Enterprise Server 16.0Package registry (OSV)
suse:kernel-obs-build6.12.0-160000.9.1 · SUSE:Linux Micro Extras 6.2Package registry (OSV)
suse:kernel-obs-qa6.12.0-160000.9.1 · SUSE:Linux Enterprise Server 16.0Package registry (OSV)
suse:kernel-rt6.12.0-160000.9.1 · SUSE:Linux Micro 6.2Package registry (OSV)
suse:kernel-source6.12.0-160000.9.1 · SUSE:Linux Micro 6.2Package registry (OSV)
suse:kernel-syms6.12.0-160000.9.1 · SUSE:Linux Enterprise Server 16.0Package registry (OSV)
suse:kernel-zfcpdump6.12.0-160000.9.1 · SUSE:Linux Enterprise Server 16.0Package 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

No CVSS vector for this record, so attack conditions can't be derived.

Weakness class (CWE)

—

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✗ → ✓

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

References

Show all references (2 more)

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

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