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NVD / CVE Program· CNA Linux

CVE-2025-38193: net_sched: sch_sfq: reject invalid perturb period

MediumCVSS 5.5 · v3.1—No exploit Fix available

Noroxi assessment

Priority: Monitor (action score 22/100)

  • 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: 0.21% (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 0357da9149eac621f39e235a135ebf155f01f7c3, 2254d038dab9c194fe6a4b1ce31034f42e91a6e5, 590b2d7d0beadba2aa576708a05a05f0aae39295; azl3 kernel 6.6.92.2-2 on Azure Linux 3.0 6.6.96.1-1; azl3 kernel 6.6.96.1-1 on Azure Linux 3.0 6.6.96.1-1.
  • Severity is disputed: the assigning authority (CNA) scores it 7.8, NVD 5.5.

Low priority for now. Upgrade to Linux Linux 0357da9149eac621f39e235a135ebf155f01f7c3, 2254d038dab9c194fe6a4b1ce31034f42e91a6e5, 590b2d7d0beadba2aa576708a05a05f0aae39295; azl3 kernel 6.6.92.2-2 on Azure Linux 3.0 6.6.96.1-1; azl3 kernel 6.6.96.1-1 on Azure Linux 3.0 6.6.96.1-1 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_sfq: reject invalid perturb period Gerrard Tai reported that SFQ perturb_period has no range check yet, and this can be used to trigger a race condition fixed in a separate patch. We want to make sure ctl->perturb_period * HZ will not overflow and is positive. tc qd add dev lo root sfq perturb -10 # negative value : error Error: sch_sfq: invalid perturb period. tc qd add dev lo root sfq perturb 1000000000 # too big : error Error: sch_sfq: invalid perturb period. tc qd add dev lo root sfq perturb 2000000 # acceptable value tc -s -d qd sh dev lo qdisc sfq 8005: root refcnt 2 limit 127p quantum 64Kb depth 127 flows 128 divisor 1024 perturb 2000000sec Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0) backlog 0b 0p requeues 0

Published
Jul 4, 2025
Updated
Oct 15, 2026
EPSS
0.2% · 11th percentile

Report tools

JSON

Action score

22

Monitor

Low priority for now.

CVSS
22 / 40 · 5.5 / 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
5.5
CNA · Linux
7.8
2.3 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.

Follow CVE-2025-38193

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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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

    • 2.6.12affected
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before e0936ff56be4e08ad5b60ec26971eae0c40af305affected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 2254d038dab9c194fe6a4b1ce31034f42e91a6e5affected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 956b5aebb349449b38d920d444ca1392d43719d1affected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before b11a50544af691b787384089b68f740ae20a441baffected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 0357da9149eac621f39e235a135ebf155f01f7c3affected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before f9b97d466e6026ccbdda30bb5b71965b67ccbc82affected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 590b2d7d0beadba2aa576708a05a05f0aae39295affected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 7ca52541c05c832d32b112274f81a985101f9ba8affected · git
    • before 2.6.12not affected · semver
Affected versions · NVD (10)

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 5.10.240
  • linux linux kernel5.11 and later · before 5.15.186
  • linux linux kernel5.16 and later · before 6.1.142
  • linux linux kernel6.2 and later · before 6.6.95
  • linux linux kernel2.6.13 and later · before 5.4.297
  • linux linux kernel6.13 and later · before 6.15.4
  • linux linux kernel6.7 and later · before 6.12.35
  • linux linux kernel2.6.12
  • linux linux kernel6.16

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.147-16.1.147-1
Debian:13linuxbefore 6.12.35-16.12.35-1

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-2025-38190Jul 4, 2025 · atm: Revert atm_account_tx() if copy_from_iter_full() fails.
    22Monitor
  • ← EarlierCVE-2025-38192Jul 4, 2025 · net: clear the dst when changing skb protocol
    22Monitor
  • Later →CVE-2025-38195Jul 4, 2025 · LoongArch: Fix panic caused by NULL-PMD in huge_pte_offset()
    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 Linux0357da9149eac621f39e235a135ebf155f01f7c3Vendor (CNA)
Linux Linux2254d038dab9c194fe6a4b1ce31034f42e91a6e5Vendor (CNA)
Linux Linux590b2d7d0beadba2aa576708a05a05f0aae39295Vendor (CNA)
Linux Linux7ca52541c05c832d32b112274f81a985101f9ba8Vendor (CNA)
Linux Linux956b5aebb349449b38d920d444ca1392d43719d1Vendor (CNA)
Linux Linuxb11a50544af691b787384089b68f740ae20a441bVendor (CNA)
Linux Linuxe0936ff56be4e08ad5b60ec26971eae0c40af305Vendor (CNA)
Linux Linuxf9b97d466e6026ccbdda30bb5b71965b67ccbc82Vendor (CNA)
azl3 kernel 6.6.92.2-2 on Azure Linux 3.06.6.96.1-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
azl3 kernel 6.6.96.1-1 on Azure Linux 3.06.6.96.1-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
debian:linux6.1.147-1 · Debian:12Package 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.

Variant candidates

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

  • CVE-2026-31633294 days apartrxrpc: Fix integer overflow in rxgk_verify_response()
    39Monitor
  • CVE-2026-31649294 days apartnet: stmmac: fix integer underflow in chain mode
    39Monitor
  • CVE-2026-31659294 days apartbatman-adv: reject oversized global TT response buffers
    39Monitor
  • CVE-2026-43341308 days apartnet/ipv6: ioam6: prevent schema length wraparound in trace fill
    39Monitor
  • CVE-2026-46039327 days apartrxgk: Fix potential integer overflow in length check
    39Monitor
  • CVE-2026-46325340 days apartRDMA/rxe: Fix iova-to-va conversion for MR page sizes != PAGE_SIZE
    39Monitor

Not on record for this CVE: EPSS history · patch commit or PR link · researcher credit · 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
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-190 · Integer Overflow or Wraparound

CVSS vector

CVSS:3.1/AV:L/AC:L/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

—

References

Show all references (9 more)

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

All records