Skip to main content
cve.nowby Sazabi
← All vulnerabilities
CVE-2025-38001

net_sched: hfsc: Address reentrant enqueue adding class to eltree twice

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 5.4.294, 5.10.238, 5.15.185, 6.1.141, 6.6.93, and 3 more
None on Exploit-DB, Metasploit or GitHub
  • Exploitation: none
  • Automatable: no
  • Technical impact: total

Summary

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

Timeline

  1. CVE published
  2. CISA SSVC assessment

    Exploitation: none · Automatable: no · Technical impact: total

  3. Record last updated

Affected versions

  • Linux Linux

    From 37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea · fixed in e5bee633cc276410337d54b99f77fbc1ad8801e5; From 37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea · fixed in 6672e6c00810056acaac019fe26cdc26fee8a66c; From 37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea · fixed in 2c928b3a0b04a431ffcd6c8b7d88a267124a3a28; From 37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea · fixed in a0ec22fa20b252edbe070a9de8501eef63c17ef5; From 37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea · fixed in 295f7c579b07b5b7cf2dffe485f71cc2f27647cb; From 37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea · fixed in 2f2190ce4ca972051cac6a8d7937448f8cb9673c; From 37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea · fixed in 4e38eaaabfb7fffbb371a51150203e19eee5d70e; From 37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea · fixed in 39ed887b1dd2d6b720f87e86692ac3006cc111c8; From 37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea · fixed in ac9fe7dd8e730a103ae4481147395cc73492d786

  • Linux Linux

    5.0

  • KernelLinux

    From 5.0.0 · fixed in 5.4.294; From 5.5.0 · fixed in 5.10.238; From 5.11.0 · fixed in 5.15.185; From 5.16.0 · fixed in 6.1.141; From 6.2.0 · fixed in 6.6.93; From 6.7.0 · fixed in 6.12.32; From 6.13.0 · fixed in 6.14.10; From 6.15.0 · fixed in 6.15.1

References 10

git.kernel.org

syst3mfailure.io