Описание
In the Linux kernel, the following vulnerability has been resolved:
netfilter: nf_conntrack: use get_unaligned_be32() in tcp_sack()
The timestamp-only fast path dereferences the option stream as
*(__be32 *)ptr, which assumes 4-byte alignment that the TCP option
stream does not guarantee. Use get_unaligned_be32() instead, which
reads the value safely and already returns host byte order, so the
htonl() on the comparison constant can be dropped.
This matches the existing get_unaligned_be32() use later in the same
function.
A flaw was found in the Linux kernel's netfilter connection tracking subsystem. The TCP option processing mechanism improperly assumes memory alignment when reading packet headers. A remote attacker could exploit this vulnerability by sending crafted TCP packets with misaligned SACK options through a system running conntrack (e.g., Linux firewall/NAT using iptables/nftables), causing a memory access fault that leads to a kernel panic and Denial of Service (DoS).
Меры по смягчению последствий
Systems that do not require stateful firewall, NAT, or connection tracking can eliminate exposure by unloading the nf_conntrack kernel module. On systems where conntrack is required, exposure can be reduced by applying NOTRACK rules in the raw table to bypass connection tracking on untrusted or internet-facing interfaces, ensuring the vulnerable TCP SACK parsing code path in tcp_sack() is not reached for attacker-controlled traffic.
Затронутые пакеты
| Платформа | Пакет | Состояние | Рекомендация | Релиз |
|---|---|---|---|---|
| Red Hat Enterprise Linux 10 | kernel | Affected | ||
| Red Hat Enterprise Linux 6 | kernel | Affected | ||
| Red Hat Enterprise Linux 7 | kernel | Affected | ||
| Red Hat Enterprise Linux 7 | kernel-rt | Affected | ||
| Red Hat Enterprise Linux 9 | kernel-rt | Affected | ||
| Red Hat OpenShift Container Platform 4 | openshift/ose-rhel-coreos-8 | Affected | ||
| Red Hat OpenShift Container Platform 4 | openshift/ose-rhel-coreos-9 | Affected | ||
| Red Hat Enterprise Linux 8 | kernel-rt | Fixed | RHSA-2026:75746 | 05.10.2026 |
| Red Hat Enterprise Linux 8 | kernel | Fixed | RHSA-2026:75747 | 05.10.2026 |
| Red Hat Enterprise Linux 9 | kernel | Fixed | RHSA-2026:76739 | 08.10.2026 |
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Дополнительная информация
Статус:
EPSS
7.5 High
CVSS3
Связанные уязвимости
In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_conntrack: use get_unaligned_be32() in tcp_sack() The timestamp-only fast path dereferences the option stream as *(__be32 *)ptr, which assumes 4-byte alignment that the TCP option stream does not guarantee. Use get_unaligned_be32() instead, which reads the value safely and already returns host byte order, so the htonl() on the comparison constant can be dropped. This matches the existing get_unaligned_be32() use later in the same function.
In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_conntrack: use get_unaligned_be32() in tcp_sack() The timestamp-only fast path dereferences the option stream as *(__be32 *)ptr, which assumes 4-byte alignment that the TCP option stream does not guarantee. Use get_unaligned_be32() instead, which reads the value safely and already returns host byte order, so the htonl() on the comparison constant can be dropped. This matches the existing get_unaligned_be32() use later in the same function.
netfilter: nf_conntrack: use get_unaligned_be32() in tcp_sack()
In the Linux kernel, the following vulnerability has been resolved: n ...
In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_conntrack: use get_unaligned_be32() in tcp_sack() The timestamp-only fast path dereferences the option stream as *(__be32 *)ptr, which assumes 4-byte alignment that the TCP option stream does not guarantee. Use get_unaligned_be32() instead, which reads the value safely and already returns host byte order, so the htonl() on the comparison constant can be dropped. This matches the existing get_unaligned_be32() use later in the same function.
EPSS
7.5 High
CVSS3