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NVD / CVE Program· CNA Linux

CVE-2025-38000: sch_hfsc: Fix qlen accounting bug when using peek in hfsc_enqueue()

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: 0.24% (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 1034e3310752e8675e313f7271b348914008719a, 3f3a22eebbc32b4fa8ce9c1d5f9db214b45b9335, 3f981138109f63232a5fb7165938d4c945cc1b9d.

Low priority for now. Upgrade to Linux Linux 1034e3310752e8675e313f7271b348914008719a, 3f3a22eebbc32b4fa8ce9c1d5f9db214b45b9335, 3f981138109f63232a5fb7165938d4c945cc1b9d 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: sch_hfsc: Fix qlen accounting bug when using peek in hfsc_enqueue() When enqueuing the first packet to an HFSC class, hfsc_enqueue() calls the child qdisc's peek() operation before incrementing sch->q.qlen and sch->qstats.backlog. If the child qdisc uses qdisc_peek_dequeued(), this may trigger an immediate dequeue and potential packet drop. In such cases, qdisc_tree_reduce_backlog() is called, but the HFSC qdisc's qlen and backlog have not yet been updated, leading to inconsistent queue accounting. This can leave an empty HFSC class in the active list, causing further consequences like use-after-free. This patch fixes the bug by moving the increment of sch->q.qlen and sch->qstats.backlog before the call to the child qdisc's peek() operation. This ensures that queue length and backlog are always accurate when packet drops or dequeues are triggered during the peek.

Published
Jun 6, 2025
Updated
Oct 15, 2026
EPSS
0.2% · 15th percentile

Report tools

JSON

Action score

31

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
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.

VendorProduct
linuxlinux kernel
debiandebian 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

    • 4.8affected
    • 12d0ad3be9c3854e52ec74bb83bb6f43612827c7 and later · before 1034e3310752e8675e313f7271b348914008719aaffected · git
    • 12d0ad3be9c3854e52ec74bb83bb6f43612827c7 and later · before f9f593e34d2fb67644372c8f7b033bdc622ad228affected · git
    • 12d0ad3be9c3854e52ec74bb83bb6f43612827c7 and later · before 89c301e929a0db14ebd94b4d97764ce1d6981653affected · git
    • 12d0ad3be9c3854e52ec74bb83bb6f43612827c7 and later · before f1dde3eb17dc1b8bd07aed00004b1e05fc87a3d4affected · git
    • 12d0ad3be9c3854e52ec74bb83bb6f43612827c7 and later · before 93c276942e75de0e5bc91576300d292e968f5a02affected · git
    • 12d0ad3be9c3854e52ec74bb83bb6f43612827c7 and later · before 49b21795b8e5654a7df3d910a12e1060da4c04cfaffected · git
    • 12d0ad3be9c3854e52ec74bb83bb6f43612827c7 and later · before 3f3a22eebbc32b4fa8ce9c1d5f9db214b45b9335affected · git
    • 12d0ad3be9c3854e52ec74bb83bb6f43612827c7 and later · before 3f981138109f63232a5fb7165938d4c945cc1b9daffected · git
    • before 4.8not affected · semver
Affected versions · NVD (9)

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 5.10.238
  • linux linux kernel5.11 and later · before 5.15.185
  • linux linux kernel5.16 and later · before 6.1.141
  • linux linux kernel4.8 and later · before 5.4.294
  • linux linux kernel6.7 and later · before 6.12.31
  • linux linux kernel6.13 and later · before 6.14.9
  • linux linux kernel6.2 and later · before 6.6.93
  • linux linux kernel6.15

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:11linux-6.1before 6.1.153-1~deb11u16.1.153-1~deb11u1
Debian:12linuxbefore 6.1.147-16.1.147-1
Debian:13linuxbefore 6.12.32-16.12.32-1
Red Hat:enterprise_linux:8::baseoskpatch-patch-4_18_0-553_16_1before 0:1-10.el8_100:1-10.el8_10
Red Hat:enterprise_linux:8::baseoskpatch-patch-4_18_0-553_16_1-debuginfobefore 0:1-10.el8_100:1-10.el8_10
Red Hat:enterprise_linux:8::baseoskpatch-patch-4_18_0-553_16_1-debugsourcebefore 0:1-10.el8_100:1-10.el8_10
Red Hat:enterprise_linux:8::baseoskpatch-patch-4_18_0-553_30_1before 0:1-9.el8_100:1-9.el8_10
Red Hat:enterprise_linux:8::baseoskpatch-patch-4_18_0-553_30_1-debuginfobefore 0:1-9.el8_100:1-9.el8_10
Red Hat:enterprise_linux:8::baseoskpatch-patch-4_18_0-553_30_1-debugsourcebefore 0:1-9.el8_100:1-9.el8_10
Red Hat:enterprise_linux:8::baseoskpatch-patch-4_18_0-553_40_1before 0:1-7.el8_100:1-7.el8_10
Red Hat:enterprise_linux:8::baseoskpatch-patch-4_18_0-553_40_1-debuginfobefore 0:1-7.el8_100:1-7.el8_10
Red Hat:enterprise_linux:8::baseoskpatch-patch-4_18_0-553_40_1-debugsourcebefore 0:1-7.el8_100:1-7.el8_10
Red Hat:enterprise_linux:8::baseoskpatch-patch-4_18_0-553_53_1before 0:1-5.el8_100:1-5.el8_10
Red Hat:enterprise_linux:8::baseoskpatch-patch-4_18_0-553_53_1-debuginfobefore 0:1-5.el8_100:1-5.el8_10
Red Hat:enterprise_linux:8::baseoskpatch-patch-4_18_0-553_53_1-debugsourcebefore 0:1-5.el8_100:1-5.el8_10
Red Hat:enterprise_linux:8::baseoskpatch-patch-4_18_0-553_72_1before 0:1-2.el8_100:1-2.el8_10
Red Hat:enterprise_linux:8::baseoskpatch-patch-4_18_0-553_72_1-debuginfobefore 0:1-2.el8_100:1-2.el8_10
Red Hat:enterprise_linux:8::baseoskpatch-patch-4_18_0-553_72_1-debugsourcebefore 0:1-2.el8_100:1-2.el8_10
Red Hat:enterprise_linux:9::baseoskpatch-patch-5_14_0-570_17_1before 0:1-10.el9_60:1-10.el9_6
Red Hat:enterprise_linux:9::baseoskpatch-patch-5_14_0-570_17_1-debuginfobefore 0:1-10.el9_60:1-10.el9_6
Red Hat:enterprise_linux:9::baseoskpatch-patch-5_14_0-570_17_1-debugsourcebefore 0:1-10.el9_60:1-10.el9_6
Red Hat:rhel_aus:7.7::serverbpftoolbefore 0:3.10.0-1062.99.1.el70:3.10.0-1062.99.1.el7
Red Hat:rhel_aus:7.7::serverbpftool-debuginfobefore 0:3.10.0-1062.99.1.el70:3.10.0-1062.99.1.el7
Red Hat:rhel_aus:7.7::serverkernelbefore 0:3.10.0-1062.99.1.el70:3.10.0-1062.99.1.el7

+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-2025-37998May 29, 2025 · openvswitch: Fix unsafe attribute parsing in output_userspace()
    22Monitor
  • ← EarlierCVE-2025-38002Jun 6, 2025 · io_uring/fdinfo: grab ctx->uring_lock around io_uring_show_fdinfo()
    22Monitor
  • Later →CVE-2025-38001Jun 6, 2025 · net_sched: hfsc: Address reentrant enqueue adding class to eltree twice
    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 Linux1034e3310752e8675e313f7271b348914008719aVendor (CNA)
Linux Linux3f3a22eebbc32b4fa8ce9c1d5f9db214b45b9335Vendor (CNA)
Linux Linux3f981138109f63232a5fb7165938d4c945cc1b9dVendor (CNA)
Linux Linux49b21795b8e5654a7df3d910a12e1060da4c04cfVendor (CNA)
Linux Linux89c301e929a0db14ebd94b4d97764ce1d6981653Vendor (CNA)
Linux Linux93c276942e75de0e5bc91576300d292e968f5a02Vendor (CNA)
Linux Linuxf1dde3eb17dc1b8bd07aed00004b1e05fc87a3d4Vendor (CNA)
Linux Linuxf9f593e34d2fb67644372c8f7b033bdc622ad228Vendor (CNA)
debian:linux6.1.147-1 · Debian:12Package registry (OSV)
debian:linux-6.16.1.153-1~deb11u1 · Debian:11Package registry (OSV)
red hat:bpftool-debuginfo0:7.0.0-284.128.1.el9_2 · Red Hat:rhel_e4s:9.2::appstreamPackage registry (OSV)
red hat:kernel-64k-debug-debuginfo0:5.14.0-284.128.1.el9_2 · Red Hat:rhel_e4s:9.2::appstreamPackage registry (OSV)
red hat:kernel-64k-debug-devel0:5.14.0-284.128.1.el9_2 · Red Hat:rhel_e4s:9.2::appstreamPackage registry (OSV)
red hat:kernel-64k-debug-devel-matched0:5.14.0-284.128.1.el9_2 · Red Hat:rhel_e4s:9.2::appstreamPackage registry (OSV)
red hat:kernel-64k-debuginfo0:5.14.0-284.128.1.el9_2 · Red Hat:rhel_e4s:9.2::appstreamPackage registry (OSV)
red hat:kernel-64k-devel0:5.14.0-284.128.1.el9_2 · Red Hat:rhel_e4s:9.2::appstreamPackage registry (OSV)
red hat:kernel-64k-devel-matched0:5.14.0-284.128.1.el9_2 · Red Hat:rhel_e4s:9.2::appstreamPackage registry (OSV)
red hat:kernel-debug-debuginfo0:5.14.0-284.128.1.el9_2 · Red Hat:rhel_e4s:9.2::appstreamPackage registry (OSV)
red hat:kernel-debug-devel0:5.14.0-284.128.1.el9_2 · Red Hat:rhel_e4s:9.2::appstreamPackage registry (OSV)
red hat:kernel-debug-devel-matched0:5.14.0-284.128.1.el9_2 · Red Hat:rhel_e4s:9.2::appstreamPackage registry (OSV)
red hat:kernel-debuginfo0:5.14.0-284.128.1.el9_2 · Red Hat:rhel_e4s:9.2::appstreamPackage registry (OSV)
red hat:kernel-debuginfo-common-aarch640:5.14.0-284.128.1.el9_2 · Red Hat:rhel_e4s:9.2::appstreamPackage registry (OSV)
suse:kernel-livepatch-SLE15-SP3_Update_4915-150300.2.1 · SUSE:Linux Enterprise Live Patching 15 SP3Package registry (OSV)
suse:kernel-livepatch-SLE15-SP3_Update_5111-150300.2.1 · SUSE:Linux Enterprise Live Patching 15 SP3Package registry (OSV)
suse:kernel-livepatch-SLE15-SP3_Update_547-150300.2.1 · SUSE:Linux Enterprise Live Patching 15 SP3Package registry (OSV)
suse:kernel-livepatch-SLE15-SP6-RT_Update_021-150600.3.1 · SUSE:Linux Enterprise Live Patching 15 SP6Package registry (OSV)
suse:kernel-livepatch-SLE15-SP6-RT_Update_120-150600.2.1 · SUSE:Linux Enterprise Live Patching 15 SP6Package registry (OSV)
suse:kernel-livepatch-SLE15-SP6-RT_Update_105-150600.2.1 · SUSE:Linux Enterprise Live Patching 15 SP6Package registry (OSV)
suse:kernel-livepatch-SLE15-SP6-RT_Update_114-150600.2.1 · SUSE:Linux Enterprise Live Patching 15 SP6Package registry (OSV)
suse:kernel-livepatch-SLE15-SP6-RT_Update_514-150600.2.1 · SUSE:Linux Enterprise Live Patching 15 SP6Package registry (OSV)

+4

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.

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

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

Fixed

c
lock(&dev->lock);free(dev->buf);dev->buf = NULL;unlock(&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.

References

Show all references (9 more)

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

All records