boxscore/security
CVE · referencelatest edition

Reference page — cumulative record through Wednesday, August 19, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.

CVE-2025-38001MEDIUM
Linux Linux — net_sched: hfsc: Address reentrant enqueue adding class to eltree twice
  AV  AC  PR  UI  S  C  I  A   CVSS    EPSS   %ile   KEV
   L   L   L   N  U  N  N  H    5.5   .0041   34.7     —
AFFECTED
  Product  Versions                                    Fixed
  Linux    37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea –  —
  Linux    5.0 –                                       5.4.294
TIMELINE
  Apr 16  Reserved by Linux
  Jun 6   Published (CNA: Linux)
  Jul 30  RESCORED — CVE-2025-38001 (Linux). CVSS 7.8 → 5.5 (NVD).
CWE-835 · CNA: Linux · CVSS v3.1 · 12 references · NVD status: Modified

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

Lifecycle

Complete event history — 3 events, chronological
DateEventDetail
April 16, 2025ReservedReserved by Linux
June 6, 2025PublishedPublished (CNA: Linux)
July 30, 2026RESCOREDRESCORED — CVE-2025-38001 (Linux). CVSS 7.8 → 5.5 (NVD).

Affected

Affected products and packages — 2 rows
VendorProduct / PackageEcosystemVersion introducedFixed
LinuxLinux37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea
LinuxLinux5.05.4.294

Weaknesses

CWE-835

References (12)

Related

Authoritative record: CVE-2025-38001 at cve.org

Vendors: linux

Weaknesses: CWE-835

About this page

This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2025-38001 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Wednesday, August 19, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.