CVE-2025-38001

Aliases:UBUNTU-CVE-2025-38001DEBIAN-CVE-2025-38001
Advisory lineage Upstream: 0 Downstream: 137
Modified
Published: 06 Jun 2025, 13:41
Last modified:05 Aug 2026, 11:58

Vulnerability Summary

Overall Risk (default)
medium
31/100
CVSS Score
7.8 HIGH
v3.1 (cve.org)
EPSS Score
0.49% LOW
0% probability +0.48%
KEV
Not listed
Ransomware
No reports
Public exploits
None found
Dark Web
Not detected

Timeline

06 Jun 2025, 13:41
Published
Vulnerability first disclosed
05 Aug 2026, 11:58
Last Modified
Vulnerability information updated

Description

In the Linux kernel, the following vulnerability has been resolved: net_sched: hfsc: Address reentrant enqueue adding class to eltree twice Savino says: "We are writing to report that this recent patch (141d34391abbb315d68556b7c67ad97885407547) [1] can be bypassed, and a UAF can still occur when HFSC is utilized with NETEM. The patch only checks the cl->cl_nactive field to determine whether it is the first insertion or not [2], but this field is only incremented by init_vf [3]. By using HFSC_RSC (which uses init_ed) [4], it is possible to bypass the check and insert the class twice in the eltree. Under normal conditions, this would lead to an infinite loop in hfsc_dequeue for the reasons we already explained in this report [5]. However, if TBF is added as root qdisc and it is configured with a very low rate, it can be utilized to prevent packets from being dequeued. This behavior can be exploited to perform subsequent insertions in the HFSC eltree and cause a UAF." To fix both the UAF and the infinite loop, with netem as an hfsc child, check explicitly in hfsc_enqueue whether the class is already in the eltree whenever the HFSC_RSC flag is set. [1] https://web.git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=141d34391abbb315d68556b7c67ad97885407547 [2] https://elixir.bootlin.com/linux/v6.15-rc5/source/net/sched/sch_hfsc.c#L1572 [3] https://elixir.bootlin.com/linux/v6.15-rc5/source/net/sched/sch_hfsc.c#L677 [4] https://elixir.bootlin.com/linux/v6.15-rc5/source/net/sched/sch_hfsc.c#L1574 [5] https://lore.kernel.org/netdev/8DuRWwfqjoRDLDmBMlIfbrsZg9Gx50DHJc1ilxsEBNe2D6NMoigR_eIRIG0LOjMc3r10nUUZtArXx4oZBIdUfZQrwjcQhdinnMis_0G7VEk=@willsroot.io/T/#u

CVSS Metrics

  • v3.1•MEDIUM•Score: 5.5CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
  • v3.1•HIGH•Score: 7.8CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS Trends

Current EPSS score: 0.49%• Percentile: 41%

Techniques & Countermeasures

  • CWE-835•Loop with Unreachable Exit Condition ('Infinite Loop')

    The product contains an iteration or loop with an exit condition that cannot be reached, i.e., an infinite loop.

Affected Systems

  • debian•linux

    < 5.10.244-1 | < 6.1.147-1 | < 6.12.32-1 | < 6.12.32-1

  • debian•linux-6.1

    < 6.1.153-1~deb11u1

  • ubuntu•linux

    < 5.4.0-219.239 | < 5.15.0-143.153 | < 6.8.0-63.66

  • ubuntu•linux-allwinner-5.19

    all

  • ubuntu•linux-aws

    < 5.4.0-1148.158 | < 5.15.0-1087.94 | < 6.8.0-1031.33

  • ubuntu•linux-aws-5.0

    all

  • ubuntu•linux-aws-5.11

    all

  • ubuntu•linux-aws-5.13

    all

  • ubuntu•linux-aws-5.15

    < 5.15.0-1087.94~20.04.1

  • ubuntu•linux-aws-5.19

    all

  • ubuntu•linux-aws-5.3

    all

  • ubuntu•linux-aws-5.4

    < 5.4.0-1148.158~18.04.1

  • ubuntu•linux-aws-5.8

    all

  • ubuntu•linux-aws-6.14

    < 6.14.0-1009.9~24.04.1

  • ubuntu•linux-aws-6.2

    all

  • ubuntu•linux-aws-6.5

    all

  • ubuntu•linux-aws-6.8

    < 6.8.0-1031.33~22.04.1

  • ubuntu•linux-aws-fips

    < 5.4.0-1148.158+fips1 | all | < 5.15.0-1087.94+fips1

  • ubuntu•linux-azure

    all | < 5.4.0-1153.160 | < 5.15.0-1092.101 | < 6.8.0-1031.36

  • ubuntu•linux-azure-5.11

    all

  • ubuntu•linux-azure-5.13

    all

  • ubuntu•linux-azure-5.15

    < 5.15.0-1094.103~20.04.1

  • ubuntu•linux-azure-5.19

    all

  • ubuntu•linux-azure-5.3

    all

  • ubuntu•linux-azure-5.4

    < 5.4.0-1153.160~18.04.1

  • ubuntu•linux-azure-5.8

    all

  • ubuntu•linux-azure-6.11

    < 6.11.0-1018.18~24.04.1

  • ubuntu•linux-azure-6.2

    all

  • ubuntu•linux-azure-6.5

    all

  • ubuntu•linux-azure-6.8

    < 6.8.0-1031.36~22.04.1

  • ubuntu•linux-azure-edge

    all

  • ubuntu•linux-azure-fde

    all | all | all

  • ubuntu•linux-azure-fde-5.19

    all

  • ubuntu•linux-azure-fde-6.2

    all

  • ubuntu•linux-azure-fips

    < 5.4.0-1154.161+fips1 | all | < 5.15.0-1094.103+fips1

  • ubuntu•linux-azure-nvidia

    < 6.8.0-1019.20

  • ubuntu•linux-bluefield

    all | < 5.4.0-1107.114 | < 5.15.0-1070.72

  • ubuntu•linux-fips

    < 5.4.0-1122.132 | all | < 5.15.0-143.153+fips1 | < 6.8.0-78.78+fips1

  • ubuntu•linux-gcp

    all | < 5.4.0-1151.160 | < 5.15.0-1086.95 | < 6.8.0-1032.34

  • ubuntu•linux-gcp-5.11

    all

  • ubuntu•linux-gcp-5.13

    all

  • ubuntu•linux-gcp-5.15

    < 5.15.0-1086.95~20.04.1

  • ubuntu•linux-gcp-5.19

    all

  • ubuntu•linux-gcp-5.3

    all

  • ubuntu•linux-gcp-5.4

    < 5.4.0-1151.160~18.04.1

  • ubuntu•linux-gcp-5.8

    all

  • ubuntu•linux-gcp-6.11

    < 6.11.0-1017.17~24.04.1

  • ubuntu•linux-gcp-6.14

    < 6.14.0-1011.11~24.04.1

  • ubuntu•linux-gcp-6.2

    all

  • ubuntu•linux-gcp-6.5

    all

Showing first 50 affected entries in server-rendered view.

References (45)