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NVD / CVE Program· CNA Linux

CVE-2025-38477: net/sched: sch_qfq: Fix race condition on qfq_aggregate

Noroxi assessment

Priority: Monitor (action score 18/100)

  • 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: 0.14% (FIRST EPSS).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. Special conditions such as timing or configuration are required.
  • Fixed version: Linux Linux 466e10194ab81caa2ee6a332d33ba16bcceeeba6, 5e28d5a3f774f118896aec17a3a20a9c5c9dfc64, a6d735100f602c830c16d69fb6d780eebd8c9ae1; azl3 kernel 6.6.96.2-2 on Azure Linux 3.0 6.6.104.2-1; cbl2 kernel 5.15.186.1-1 on CBL Mariner 2.0 5.15.200.1-1.
  • Severity is disputed: the assigning authority (CNA) scores it 7.8, NVD 4.7.

Low priority for now. Upgrade to Linux Linux 466e10194ab81caa2ee6a332d33ba16bcceeeba6, 5e28d5a3f774f118896aec17a3a20a9c5c9dfc64, a6d735100f602c830c16d69fb6d780eebd8c9ae1; azl3 kernel 6.6.96.2-2 on Azure Linux 3.0 6.6.104.2-1; cbl2 kernel 5.15.186.1-1 on CBL Mariner 2.0 5.15.200.1-1 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: net/sched: sch_qfq: Fix race condition on qfq_aggregate A race condition can occur when 'agg' is modified in qfq_change_agg (called during qfq_enqueue) while other threads access it concurrently. For example, qfq_dump_class may trigger a NULL dereference, and qfq_delete_class may cause a use-after-free. This patch addresses the issue by: 1. Moved qfq_destroy_class into the critical section. 2. Added sch_tree_lock protection to qfq_dump_class and qfq_dump_class_stats.

MediumCVSS 4.7 · v3.1—No exploit Fix available
Published
Jul 28, 2025
Updated
Oct 15, 2026
EPSS
0.1% · 3th percentile

Report tools

JSON

Action score

18

Monitor

Low priority for now.

CVSS
18 / 40 · 4.7 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
4.7
CNA · Linux
7.8
3.1 point gap

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

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.

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When you'll hear from us

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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.

VendorProduct
linuxlinux kernel
debiandebian linux

Affected versions

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 kernel5.5 and later · before 5.10.241
  • linux linux kernel5.11 and later · before 5.15.190
  • linux linux kernel5.16 and later · before 6.1.147
  • linux linux kernel3.8 and later · before 5.4.297
  • linux linux kernel6.7 and later · before 6.12.40
  • linux linux kernel6.13 and later · before 6.15.8
  • linux linux kernel6.2 and later · before 6.6.100
  • linux linux kernel6.16

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

    • 3.8affected
    • 462dbc9101acd38e92eda93c0726857517a24bbd and later · before aa7a22c4d678bf649fd3a1d27debec583563414daffected · git
    • 462dbc9101acd38e92eda93c0726857517a24bbd and later · before d841aa5518508ab195b6781ad0d73ee378d713ddaffected · git
    • 462dbc9101acd38e92eda93c0726857517a24bbd and later · before c6df794000147a3a02f79984aada4ce83f8d0a1eaffected · git
    • 462dbc9101acd38e92eda93c0726857517a24bbd and later · before 466e10194ab81caa2ee6a332d33ba16bcceeeba6affected · git
    • 462dbc9101acd38e92eda93c0726857517a24bbd and later · before fbe48f06e64134dfeafa89ad23387f66ebca3527affected · git
    • 462dbc9101acd38e92eda93c0726857517a24bbd and later · before a6d735100f602c830c16d69fb6d780eebd8c9ae1affected · git
    • 462dbc9101acd38e92eda93c0726857517a24bbd and later · before c000a3a330d97f6c073ace5aa5faf94b9adb4b79affected · git
    • 462dbc9101acd38e92eda93c0726857517a24bbd and later · before 5e28d5a3f774f118896aec17a3a20a9c5c9dfc64affected · git
    • before 3.8not affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
AlmaLinux:8bpftoolbefore 4.18.0-553.72.1.el8_104.18.0-553.72.1.el8_10
AlmaLinux:8kernelbefore 4.18.0-553.72.1.el8_104.18.0-553.72.1.el8_10
AlmaLinux:8kernel-abi-stablelistsbefore 4.18.0-553.72.1.el8_104.18.0-553.72.1.el8_10
AlmaLinux:8kernel-corebefore 4.18.0-553.72.1.el8_104.18.0-553.72.1.el8_10
AlmaLinux:8kernel-cross-headersbefore 4.18.0-553.72.1.el8_104.18.0-553.72.1.el8_10
AlmaLinux:8kernel-debugbefore 4.18.0-553.72.1.el8_104.18.0-553.72.1.el8_10
AlmaLinux:8kernel-debug-corebefore 4.18.0-553.72.1.el8_104.18.0-553.72.1.el8_10
AlmaLinux:8kernel-debug-develbefore 4.18.0-553.72.1.el8_104.18.0-553.72.1.el8_10
AlmaLinux:8kernel-debug-modulesbefore 4.18.0-553.72.1.el8_104.18.0-553.72.1.el8_10
AlmaLinux:8kernel-debug-modules-extrabefore 4.18.0-553.72.1.el8_104.18.0-553.72.1.el8_10
AlmaLinux:8kernel-develbefore 4.18.0-553.72.1.el8_104.18.0-553.72.1.el8_10
AlmaLinux:8kernel-docbefore 4.18.0-553.72.1.el8_104.18.0-553.72.1.el8_10
AlmaLinux:8kernel-headersbefore 4.18.0-553.72.1.el8_104.18.0-553.72.1.el8_10
AlmaLinux:8kernel-modulesbefore 4.18.0-553.72.1.el8_104.18.0-553.72.1.el8_10
AlmaLinux:8kernel-modules-extrabefore 4.18.0-553.72.1.el8_104.18.0-553.72.1.el8_10
AlmaLinux:8kernel-toolsbefore 4.18.0-553.72.1.el8_104.18.0-553.72.1.el8_10
AlmaLinux:8kernel-tools-libsbefore 4.18.0-553.72.1.el8_104.18.0-553.72.1.el8_10
AlmaLinux:8kernel-tools-libs-develbefore 4.18.0-553.72.1.el8_104.18.0-553.72.1.el8_10
AlmaLinux:8kernel-zfcpdumpbefore 4.18.0-553.72.1.el8_104.18.0-553.72.1.el8_10
AlmaLinux:8kernel-zfcpdump-corebefore 4.18.0-553.72.1.el8_104.18.0-553.72.1.el8_10
AlmaLinux:8kernel-zfcpdump-develbefore 4.18.0-553.72.1.el8_104.18.0-553.72.1.el8_10
AlmaLinux:8kernel-zfcpdump-modulesbefore 4.18.0-553.72.1.el8_104.18.0-553.72.1.el8_10
AlmaLinux:8kernel-zfcpdump-modules-extrabefore 4.18.0-553.72.1.el8_104.18.0-553.72.1.el8_10
AlmaLinux:8perfbefore 4.18.0-553.72.1.el8_104.18.0-553.72.1.el8_10

+96

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-2025-38475Jul 28, 2025 · smc: Fix various oops due to inet_sock type confusion.
    22Monitor
  • ← EarlierCVE-2025-38476Jul 28, 2025 · rpl: Fix use-after-free in rpl_do_srh_inline().
    31Monitor
  • Later →CVE-2025-38480Jul 28, 2025 · comedi: Fix use of uninitialized data in insn_rw_emulate_bits()
    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 / packageFixed versionSource
Linux Linux466e10194ab81caa2ee6a332d33ba16bcceeeba6Vendor (CNA)
Linux Linux5e28d5a3f774f118896aec17a3a20a9c5c9dfc64Vendor (CNA)
Linux Linuxa6d735100f602c830c16d69fb6d780eebd8c9ae1Vendor (CNA)
Linux Linuxaa7a22c4d678bf649fd3a1d27debec583563414dVendor (CNA)
Linux Linuxc000a3a330d97f6c073ace5aa5faf94b9adb4b79Vendor (CNA)
Linux Linuxc6df794000147a3a02f79984aada4ce83f8d0a1eVendor (CNA)
Linux Linuxd841aa5518508ab195b6781ad0d73ee378d713ddVendor (CNA)
Linux Linuxfbe48f06e64134dfeafa89ad23387f66ebca3527Vendor (CNA)
azl3 kernel 6.6.96.2-2 on Azure Linux 3.06.6.104.2-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
cbl2 kernel 5.15.186.1-1 on CBL Mariner 2.05.15.200.1-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
almalinux:bpftool4.18.0-553.72.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel4.18.0-553.72.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-abi-stablelists4.18.0-553.72.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-core4.18.0-553.72.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-cross-headers4.18.0-553.72.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-debug4.18.0-553.72.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-debug-core4.18.0-553.72.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-debug-devel4.18.0-553.72.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-debug-modules4.18.0-553.72.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-debug-modules-extra4.18.0-553.72.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-devel4.18.0-553.72.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-doc4.18.0-553.72.1.el8_10 · AlmaLinux:8Package registry (OSV)
debian:linux6.1.147-1 · Debian:12Package registry (OSV)
red hat:bpftool0:4.18.0-553.72.1.el8_10 · Red Hat:enterprise_linux:8::baseosPackage registry (OSV)
red hat:bpftool-debuginfo0:4.18.0-553.72.1.el8_10 · Red Hat:enterprise_linux:8::baseosPackage registry (OSV)
red hat:kernel0:4.18.0-553.72.1.el8_10 · Red Hat:enterprise_linux:8::baseosPackage registry (OSV)
red hat:kernel-abi-stablelists0:4.18.0-553.72.1.el8_10 · Red Hat:enterprise_linux:8::baseosPackage registry (OSV)
red hat:kernel-core0:4.18.0-553.72.1.el8_10 · Red Hat:enterprise_linux:8::baseosPackage registry (OSV)
red hat:kernel-debug0:4.18.0-553.72.1.el8_10 · Red Hat:enterprise_linux:8::baseosPackage registry (OSV)
red hat:kernel-debug-core0:4.18.0-553.72.1.el8_10 · Red Hat:enterprise_linux:8::baseosPackage registry (OSV)

+18

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.
  • Special conditions such as timing or configuration are required.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
High
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-362 · Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

CVSS vector

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

nvd-primary

Attack context

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

ATT&CK techniques

—

Change log

  1. Fix✗ → ✓

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

References

Show all references (10 more)

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

All records