Описание
In the Linux kernel, the following vulnerability has been resolved:
net/sched: fix pedit partial COW leading to page cache corruption
tcf_pedit_act() computes the COW range for skb_ensure_writable()
once before the key loop using tcfp_off_max_hint, but the hint does
not account for the runtime header offset added by typed keys. This
can leave part of the write region un-COW'd.
Fix by moving skb_ensure_writable() inside the per-key loop where
the actual write offset is known, and add overflow checking on the
offset arithmetic. For negative offsets (e.g. Ethernet header edits
at ingress), use skb_cow() to COW the headroom instead. Guard
offset_valid() against INT_MIN, where negation is undefined.
A flaw was found in the Linux kernel's traffic control packet editing (pedit) subsystem. In tcf_pedit_act(), the copy-on-write (COW) range for skb_ensure_writable() is computed once before iterating over edit keys, but the calculation does not account for runtime header offsets added by typed keys. This can leave part of the target write region without a proper copy-on-write, leading to an out-of-bounds write that corrupts page cache memory. A local attacker with the ability to configure traffic control rules could exploit this to escalate privileges or crash the system.
Отчет
Red Hat rates this flaw as Important severity. This vulnerability is in the kernel's traffic control (tc) pedit action, which requires CAP_NET_ADMIN capability to configure. By default in Red Hat Enterprise Linux, this limits exploitation to the root user or processes explicitly granted network administration capabilities. However, in some circumstances unprivileged users may obtain CAP_NET_ADMIN within user namespaces. Successful exploitation could lead to arbitrary code execution in kernel context or a system crash. Red Hat Enterprise Linux 7 and earlier are not affected. Within OpenShift Container Platform, the vulnerable module is not loaded by default, reducing the severity to Low.
Меры по смягчению последствий
See the security bulletin for a detailed mitigation procedure.
Затронутые пакеты
| Платформа | Пакет | Состояние | Рекомендация | Релиз |
|---|---|---|---|---|
| Red Hat Enterprise Linux 10 | libkrun | Not affected | ||
| Red Hat Enterprise Linux 6 | kernel | Not affected | ||
| Red Hat Enterprise Linux 7 | kernel | Not affected | ||
| Red Hat Enterprise Linux 7 | kernel-rt | Not affected | ||
| NVIDIA for RHEL 10 | kernel | Fixed | RHSA-2026:27709 | 22.06.2026 |
| NVIDIA for RHEL 10 | kernel | Fixed | RHSA-2026:33666 | 30.06.2026 |
| Red Hat Enterprise Linux 10 | kernel | Fixed | RHSA-2026:27288 | 20.06.2026 |
| Red Hat Enterprise Linux 10 | kpatch-patch | Fixed | RHSA-2026:33225 | 29.06.2026 |
| Red Hat Enterprise Linux 10.0 Extended Update Support | kernel | Fixed | RHSA-2026:27731 | 22.06.2026 |
| Red Hat Enterprise Linux 8 | kernel-rt | Fixed | RHSA-2026:27354 | 19.06.2026 |
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Дополнительная информация
Статус:
EPSS
6.7 Medium
CVSS3
Связанные уязвимости
In the Linux kernel, the following vulnerability has been resolved: net/sched: fix pedit partial COW leading to page cache corruption tcf_pedit_act() computes the COW range for skb_ensure_writable() once before the key loop using tcfp_off_max_hint, but the hint does not account for the runtime header offset added by typed keys. This can leave part of the write region un-COW'd. Fix by moving skb_ensure_writable() inside the per-key loop where the actual write offset is known, and add overflow checking on the offset arithmetic. For negative offsets (e.g. Ethernet header edits at ingress), use skb_cow() to COW the headroom instead. Guard offset_valid() against INT_MIN, where negation is undefined.
In the Linux kernel, the following vulnerability has been resolved: net/sched: fix pedit partial COW leading to page cache corruption tcf_pedit_act() computes the COW range for skb_ensure_writable() once before the key loop using tcfp_off_max_hint, but the hint does not account for the runtime header offset added by typed keys. This can leave part of the write region un-COW'd. Fix by moving skb_ensure_writable() inside the per-key loop where the actual write offset is known, and add overflow checking on the offset arithmetic. For negative offsets (e.g. Ethernet header edits at ingress), use skb_cow() to COW the headroom instead. Guard offset_valid() against INT_MIN, where negation is undefined.
net/sched: fix pedit partial COW leading to page cache corruption
In the Linux kernel, the following vulnerability has been resolved: n ...
In the Linux kernel, the following vulnerability has been resolved: net/sched: fix pedit partial COW leading to page cache corruption tcf_pedit_act() computes the COW range for skb_ensure_writable() once before the key loop using tcfp_off_max_hint, but the hint does not account for the runtime header offset added by typed keys. This can leave part of the write region un-COW'd. Fix by moving skb_ensure_writable() inside the per-key loop where the actual write offset is known, and add overflow checking on the offset arithmetic. For negative offsets (e.g. Ethernet header edits at ingress), use skb_cow() to COW the headroom instead. Guard offset_valid() against INT_MIN, where negation is undefined.
EPSS
6.7 Medium
CVSS3