CVE - CVE-2025-38001

CVE-ID
CVE-2025-38001	Learn more at National Vulnerability Database (NVD) • CVSS Severity Rating • Fix Information • Vulnerable Software Versions • SCAP Mappings • CPE Information
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
References
Note: References are provided for the convenience of the reader to help distinguish between vulnerabilities. The list is not intended to be complete.
MISC:https://git.kernel.org/stable/c/295f7c579b07b5b7cf2dffe485f71cc2f27647cb URL:https://git.kernel.org/stable/c/295f7c579b07b5b7cf2dffe485f71cc2f27647cb MISC:https://git.kernel.org/stable/c/2c928b3a0b04a431ffcd6c8b7d88a267124a3a28 URL:https://git.kernel.org/stable/c/2c928b3a0b04a431ffcd6c8b7d88a267124a3a28 MISC:https://git.kernel.org/stable/c/2f2190ce4ca972051cac6a8d7937448f8cb9673c URL:https://git.kernel.org/stable/c/2f2190ce4ca972051cac6a8d7937448f8cb9673c MISC:https://git.kernel.org/stable/c/39ed887b1dd2d6b720f87e86692ac3006cc111c8 URL:https://git.kernel.org/stable/c/39ed887b1dd2d6b720f87e86692ac3006cc111c8 MISC:https://git.kernel.org/stable/c/4e38eaaabfb7fffbb371a51150203e19eee5d70e URL:https://git.kernel.org/stable/c/4e38eaaabfb7fffbb371a51150203e19eee5d70e MISC:https://git.kernel.org/stable/c/6672e6c00810056acaac019fe26cdc26fee8a66c URL:https://git.kernel.org/stable/c/6672e6c00810056acaac019fe26cdc26fee8a66c MISC:https://git.kernel.org/stable/c/a0ec22fa20b252edbe070a9de8501eef63c17ef5 URL:https://git.kernel.org/stable/c/a0ec22fa20b252edbe070a9de8501eef63c17ef5 MISC:https://git.kernel.org/stable/c/e5bee633cc276410337d54b99f77fbc1ad8801e5 URL:https://git.kernel.org/stable/c/e5bee633cc276410337d54b99f77fbc1ad8801e5
Assigning CNA
kernel.org
Date Record Created
20250416	Disclaimer: The record creation date may reflect when the CVE ID was allocated or reserved, and does not necessarily indicate when this vulnerability was discovered, shared with the affected vendor, publicly disclosed, or updated in CVE.
Phase (Legacy)
Assigned (20250416)
Votes (Legacy)

Comments (Legacy)

Proposed (Legacy)
N/A
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