CVE-2025-38001

MEDIUM EPSS 28.7%
Published Jun 6, 20251y ago · Modified Jun 17, 20261w ago
5.5 CVSS 3.1
Medium
Find Similar
Published Jun 6, 2025 1y ago
Last Modified Jun 17, 2026 1w ago

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 Details

Base Score
5.5
Exploitability
1.8
Impact
3.6
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Attack Vector Local
Attack Complexity Low
Privileges Required Low
User Interaction None
Scope Unchanged
Confidentiality None
Integrity None
Availability High

Threat Intelligence

EPSS Exploit Probability
28.7% percentile
Exploit & Patch Status
No Known Exploit
Patch Available

Weaknesses 1

CWE-835

Affected Products 17

VendorProductVersionRange
linuxlinux_kernel*≥5.0.1  –  <5.4.294
linuxlinux_kernel*≥5.5  –  <5.10.238
linuxlinux_kernel*≥5.11  –  <5.15.185
linuxlinux_kernel*≥5.16  –  <6.1.141
linuxlinux_kernel*≥6.2  –  <6.6.93
linuxlinux_kernel*≥6.7  –  <6.12.32
linuxlinux_kernel*≥6.13  –  <6.14.10
linuxlinux_kernel*≥6.15  –  <6.15.1
linuxlinux_kernel5.0any
linuxlinux_kernel5.0any
linuxlinux_kernel5.0any
linuxlinux_kernel5.0any
linuxlinux_kernel5.0any
linuxlinux_kernel5.0any
linuxlinux_kernel5.0any
debiandebian_linux11.0any
debiandebian_linux12.0any

References 12

  • git.kernel.org https://git.kernel.org/stable/c/295f7c579b07b5b7cf2dffe485f71cc2f27647cb
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/2c928b3a0b04a431ffcd6c8b7d88a267124a3a28
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/2f2190ce4ca972051cac6a8d7937448f8cb9673c
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/39ed887b1dd2d6b720f87e86692ac3006cc111c8
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/4e38eaaabfb7fffbb371a51150203e19eee5d70e
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/6672e6c00810056acaac019fe26cdc26fee8a66c
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/a0ec22fa20b252edbe070a9de8501eef63c17ef5
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/ac9fe7dd8e730a103ae4481147395cc73492d786
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/e5bee633cc276410337d54b99f77fbc1ad8801e5
    Patch
  • lists.debian.org https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html
    Third Party Advisory
  • lists.debian.org https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html
    Third Party Advisory
  • syst3mfailure.io https://syst3mfailure.io/rbtree-family-drama/
    Third Party Advisory

Remediation

  • git.kernel.org https://git.kernel.org/stable/c/295f7c579b07b5b7cf2dffe485f71cc2f27647cb
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/2c928b3a0b04a431ffcd6c8b7d88a267124a3a28
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/2f2190ce4ca972051cac6a8d7937448f8cb9673c
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/39ed887b1dd2d6b720f87e86692ac3006cc111c8
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/4e38eaaabfb7fffbb371a51150203e19eee5d70e
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/6672e6c00810056acaac019fe26cdc26fee8a66c
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/a0ec22fa20b252edbe070a9de8501eef63c17ef5
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/ac9fe7dd8e730a103ae4481147395cc73492d786
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/e5bee633cc276410337d54b99f77fbc1ad8801e5
    Patch