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

An update of the linux package has been released.

It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2023-2025-1037 advisory.

    In the Linux kernel, the following vulnerability has been resolved:

    btrfs: check folio mapping after unlock in relocate_one_folio() (CVE-2024-56758)

    In the Linux kernel, the following vulnerability has been resolved:

    hrtimers: Force migrate away hrtimers queued after CPUHP_AP_HRTIMERS_DYING (CVE-2025-21816)

    In the Linux kernel, the following vulnerability has been resolved:

    sch_hfsc: Fix qlen accounting bug when using peek in hfsc_enqueue() (CVE-2025-38000)

    In the Linux kernel, the following vulnerability has been resolved:

    net_sched: hfsc: Address reentrant enqueue adding class to eltree twice (CVE-2025-38001)

    In the Linux kernel, the following vulnerability has been resolved:

    can: bcm: add locking for bcm_op runtime updates (CVE-2025-38004)

Tenable has extracted the preceding description block directly from the tested product security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The version of kernel installed on the remote host is prior to 5.4.294-212.419. It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2KERNEL-5.4-2025-103 advisory.

    In the Linux kernel, the following vulnerability has been resolved:

    scsi: target: Fix WRITE_SAME No Data Buffer crash

    In newer version of the SBC specs, we have a NDOB bit that indicates thereis no data buffer that gets     written out. If this bit is set using commandslike sg_write_same --ndob we will crash in     target_core_iblock/file'sexecute_write_same handlers when we go to access the se_cmd->t_data_sgbecause its     NULL.

    This patch adds a check for the NDOB bit in the common WRITE SAME codebecause we don't support it. And, it     adds a check for zero SG elements ineach handler in case the initiator tries to send a normal WRITE SAME     withno data buffer. (CVE-2022-21546)

    In the Linux kernel, the following vulnerability has been resolved:

    mm/khugepaged: fix ->anon_vma race (CVE-2023-52935)

    In the Linux kernel, the following vulnerability has been resolved:

    of: module: add buffer overflow check in of_modalias() (CVE-2024-38541)

    In the Linux kernel, the following vulnerability has been resolved:

    irqchip/gic-v2m: Prevent use after free of gicv2m_get_fwnode() (CVE-2025-37819)

    In the Linux kernel, the following vulnerability has been resolved:

    net_sched: hfsc: Fix a UAF vulnerability in class with netem as child qdisc (CVE-2025-37890)

    In the Linux kernel, the following vulnerability has been resolved:

    net_sched: qfq: Fix double list add in class with netem as child qdisc (CVE-2025-37913)

    In the Linux kernel, the following vulnerability has been resolved:

    net_sched: drr: Fix double list add in class with netem as child qdisc (CVE-2025-37915)

    In the Linux kernel, the following vulnerability has been resolved:

    tracing: Fix oob write in trace_seq_to_buffer() (CVE-2025-37923)

    In the Linux kernel, the following vulnerability has been resolved:

    iommu/amd: Fix potential buffer overflow in parse_ivrs_acpihid (CVE-2025-37927)

    In the Linux kernel, the following vulnerability has been resolved:

    sch_htb: make htb_qlen_notify() idempotent (CVE-2025-37932)

    In the Linux kernel, the following vulnerability has been resolved:

    xenbus: Use kref to track req lifetime (CVE-2025-37949)

    In the Linux kernel, the following vulnerability has been resolved:

    module: ensure that kobject_put() is safe for module type kobjects (CVE-2025-37995)

    In the Linux kernel, the following vulnerability has been resolved:

    openvswitch: Fix unsafe attribute parsing in output_userspace() (CVE-2025-37998)

    In the Linux kernel, the following vulnerability has been resolved:

    sch_hfsc: Fix qlen accounting bug when using peek in hfsc_enqueue() (CVE-2025-38000)

    In the Linux kernel, the following vulnerability has been resolved:

    net_sched: hfsc: Address reentrant enqueue adding class to eltree twice (CVE-2025-38001)

    In the Linux kernel, the following vulnerability has been resolved:

    can: bcm: add locking for bcm_op runtime updates (CVE-2025-38004)

Tenable has extracted the preceding description block directly from the tested product security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The version of kernel installed on the remote host is prior to 5.10.238-231.953. It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2KERNEL-5.10-2025-095 advisory.

    In the Linux kernel, the following vulnerability has been resolved:

    net/sched: act_mirred: don't override retval if we already lost the skb (CVE-2024-26739)

    In the Linux kernel, the following vulnerability has been resolved:

    of: module: add buffer overflow check in of_modalias() (CVE-2024-38541)

    In the Linux kernel, the following vulnerability has been resolved:

    btrfs: don't BUG_ON() when 0 reference count at btrfs_lookup_extent_info() (CVE-2024-46751)

    In the Linux kernel, the following vulnerability has been resolved:

    bpf: Fix helper writes to read-only maps (CVE-2024-49861)

    In the Linux kernel, the following vulnerability has been resolved:

    irqchip/gic-v2m: Prevent use after free of gicv2m_get_fwnode() (CVE-2025-37819)

    In the Linux kernel, the following vulnerability has been resolved:

    net_sched: hfsc: Fix a UAF vulnerability in class with netem as child qdisc (CVE-2025-37890)

    In the Linux kernel, the following vulnerability has been resolved:

    net_sched: qfq: Fix double list add in class with netem as child qdisc (CVE-2025-37913)

    In the Linux kernel, the following vulnerability has been resolved:

    net_sched: drr: Fix double list add in class with netem as child qdisc (CVE-2025-37915)

    In the Linux kernel, the following vulnerability has been resolved:

    tracing: Fix oob write in trace_seq_to_buffer() (CVE-2025-37923)

    In the Linux kernel, the following vulnerability has been resolved:

    iommu/amd: Fix potential buffer overflow in parse_ivrs_acpihid (CVE-2025-37927)

    In the Linux kernel, the following vulnerability has been resolved:

    xenbus: Use kref to track req lifetime (CVE-2025-37949)

    In the Linux kernel, the following vulnerability has been resolved:

    net_sched: Flush gso_skb list too during ->change() (CVE-2025-37992)

    In the Linux kernel, the following vulnerability has been resolved:

    module: ensure that kobject_put() is safe for module type kobjects (CVE-2025-37995)

    In the Linux kernel, the following vulnerability has been resolved:

    openvswitch: Fix unsafe attribute parsing in output_userspace() (CVE-2025-37998)

    In the Linux kernel, the following vulnerability has been resolved:

    sch_hfsc: Fix qlen accounting bug when using peek in hfsc_enqueue() (CVE-2025-38000)

    In the Linux kernel, the following vulnerability has been resolved:

    net_sched: hfsc: Address reentrant enqueue adding class to eltree twice (CVE-2025-38001)

    In the Linux kernel, the following vulnerability has been resolved:

    can: bcm: add locking for bcm_op runtime updates (CVE-2025-38004)

Tenable has extracted the preceding description block directly from the tested product security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

ID	Name	Product	Family	Severity
240519	Photon OS 4.0: Linux PHSA-2025-4.0-0814	Nessus	PhotonOS Local Security Checks	medium
240349	Photon OS 5.0: Linux PHSA-2025-5.0-0533	Nessus	PhotonOS Local Security Checks	high
240328	Amazon Linux 2023 : bpftool, kernel, kernel-devel (ALAS2023-2025-1037)	Nessus	Amazon Linux Local Security Checks	medium
240323	Amazon Linux 2 : kernel (ALASKERNEL-5.4-2025-103)	Nessus	Amazon Linux Local Security Checks	critical
240309	Amazon Linux 2 : kernel (ALASKERNEL-5.10-2025-095)	Nessus	Amazon Linux Local Security Checks	high

Detections

Analytics

CVE-2025-38001

medium

Tenable Plugins

medium

high

medium

critical

high