LiveActive security incident?Get immediate response
CVE Record

CVE-2025-37914: net_sched: ets: Fix double list add in class with netem as child qdisc

In the Linux kernel, the following vulnerability has been resolved: net_sched: ets: Fix double list add in class with netem as child qdisc As described in Gerrard's report [1], there are use cases where a netem child qdisc will make the parent qdisc's enqueue callback reentrant. In the case of ets, there won't be a UAF, but the code will add the same classifier to the list twice, which will cause memory corruption. In addition to checking for qlen being zero, this patch checks whether the class was already added to the active_list (cl_is_active) before doing the addition to cater for the reentrant case. [1] https://lore.kernel.org/netdev/CAHcdcOm+03OD2j6R0=YHKqmy=VgJ8xEOKuP6c7mSgnp-TEJJbw@mail.gmail.com/

HighCVSS 7.8Not KEV-listedUpdated
Discuss exposureBack to CVEs
Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

A flaw in Linux traffic scheduling can corrupt kernel memory when an ETS scheduler has a netem child and reentrant packet processing occurs. A local, low-privileged attacker may be able to compromise confidentiality, integrity, and availability, but exposure depends on this specific configuration.

Executive priority

Treat as a high-priority, configuration-dependent kernel issue. Accelerate remediation on shared, multi-user, or sensitive systems using the affected traffic-control arrangement; routine prioritization is reasonable where that configuration is demonstrably absent.

Technical view

Reentrant execution of the ETS enqueue callback can add the same classifier to active_list twice when netem is a child qdisc, causing memory corruption. The fix checks cl_is_active before list insertion. The kernel report explicitly states this is not a use-after-free in ETS.

Likely exposure

Exposure is limited to affected Linux kernels using an ETS qdisc with netem as a child. The supplied version data identifies affected releases but does not provide unambiguous distribution-specific ranges; confirm installed vendor kernel packages and backports.

Exploitation context

The CVSS 3.1 assessment is 7.8, requiring local access, low privileges, low complexity, and no user interaction. CISA KEV status is false, and the supplied sources provide no evidence of active exploitation or a public weaponized exploit.

Researcher notes

The vulnerable condition is a duplicate active_list insertion caused by an enqueue callback becoming reentrant through netem. The correction adds an active-state check alongside the zero-queue-length check. No CWE was supplied, and evidence does not establish practical exploitation reliability or affected distribution package boundaries.

Mitigation direction

  • Install a vendor kernel update containing the applicable Linux stable fix.
  • Confirm distribution backports rather than relying only on the displayed kernel version.
  • If patching is delayed, avoid the ETS-with-netem configuration where operationally safe.
  • Review Linux and distribution guidance for branch-specific fixed packages.

Validation and detection

  • Inventory Linux kernel versions across hosts and container nodes.
  • Identify systems configuring ETS qdiscs with netem children.
  • Verify the installed kernel includes the relevant stable commit or vendor backport.
  • After updating, confirm hosts booted into the corrected kernel.
  • Monitor exposed systems for kernel crashes or memory-corruption symptoms.
Prepared
Confidence
high
Sources
7

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cve · low confidence lookup

CVE-2025-37914 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

Open ATT&CK lookup
Vulnerability profileCVE Program record
Severity
High
CVSS
7.8 (3.1)
Known Exploited
No
Published

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

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

1CVSS vectors
3Timeline events
1ADP providers
10Source links

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
7.8CVSS 3.1HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H1.85.9Linux

Vulnerability scoring details

Base CVSS 3.1 score

7.8High
CVSS 3.1 vector shape for CVE-2025-37914Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

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

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CVECVE Program Container

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinuxdcc68b4d8084e1ac9af0d4022d6b1aff6a139a33, dcc68b4d8084e1ac9af0d4022d6b1aff6a139a33, dcc68b4d8084e1ac9af0d4022d6b1aff6a139a33, dcc68b4d8084e1ac9af0d4022d6b1aff6a139a33, dcc68b4d8084e1ac9af0d4022d6b1aff6a139a33, dcc68b4d8084e1ac9af0d4022d6b1aff6a139a33, dcc68b4d8084e1ac9af0d4022d6b1aff6a139a33unaffected
LinuxLinux5.6, 0, 5.10.238, 5.15.182, 6.1.138, 6.6.90, 6.12.28, 6.14.6, 6.15affected
Weakness

CWE details

No CWE listed

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.