Описание
In the Linux kernel, the following vulnerability has been resolved:
inet: RAW sockets using IPPROTO_RAW MUST drop incoming ICMP
Yizhou Zhao reported that simply having one RAW socket on protocol
IPPROTO_RAW (255) was dangerous.
socket(AF_INET, SOCK_RAW, 255);
A malicious incoming ICMP packet can set the protocol field to 255
and match this socket, leading to FNHE cache changes.
inner = IP(src="192.168.2.1", dst="8.8.8.8", proto=255)/Raw("TEST")
pkt = IP(src="192.168.1.1", dst="192.168.2.1")/ICMP(type=3, code=4, nexthopmtu=576)/inner
"man 7 raw" states:
A protocol of IPPROTO_RAW implies enabled IP_HDRINCL and is able
to send any IP protocol that is specified in the passed header.
Receiving of all IP protocols via IPPROTO_RAW is not possible
using raw sockets.
Make sure we drop these malicious packets.
A flaw was found in the Linux kernel's handling of RAW sockets using IPPROTO_RAW. A remote attacker could send a specially crafted ICMP (Internet Control Message Protocol) packet. This malicious packet could set the protocol field to 255, causing it to be processed by a RAW socket configured for IPPROTO_RAW. This leads to unintended FNHE (Flow N-tuple Hash Entry) cache changes, which could result in unexpected network behavior.
Отчет
Incoming ICMP or ICMPv6 error processing could incorrectly treat an embedded protocol value of IPPROTO_RAW as deliverable to a local raw socket. A remote attacker can send a crafted ICMP error with an inner IP header using protocol 255 and may cause FNHE route cache changes, such as route exception or PMTU state changes, when a matching IPPROTO_RAW socket exists on the target. For the CVSS the PR:N is used because the remote sender does not need privileges on the victim host, although reliable triggering depends on a local process having created an IPPROTO_RAW raw socket. The issue is network reachable but has an important environmental precondition, so AC:H is used. Impact is mainly denial of service and low integrity impact through route cache manipulation, not memory corruption or privilege escalation.
Меры по смягчению последствий
Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
Затронутые пакеты
| Платформа | Пакет | Состояние | Рекомендация | Релиз |
|---|---|---|---|---|
| Red Hat Enterprise Linux 6 | kernel | Out of support scope | ||
| 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 Enterprise Linux 10 | kernel | Fixed | RHSA-2026:64775 | 08.09.2026 |
| Red Hat Enterprise Linux 8 | kernel-rt | Fixed | RHSA-2026:68532 | 17.09.2026 |
| Red Hat Enterprise Linux 8 | kernel | Fixed | RHSA-2026:68531 | 17.09.2026 |
| Red Hat Enterprise Linux 9 | kernel | Fixed | RHSA-2026:66180 | 10.09.2026 |
| Red Hat Enterprise Linux 9 | kernel | Fixed | RHSA-2026:66180 | 10.09.2026 |
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Дополнительная информация
Статус:
6.5 Medium
CVSS3
Связанные уязвимости
In the Linux kernel, the following vulnerability has been resolved: inet: RAW sockets using IPPROTO_RAW MUST drop incoming ICMP Yizhou Zhao reported that simply having one RAW socket on protocol IPPROTO_RAW (255) was dangerous. socket(AF_INET, SOCK_RAW, 255); A malicious incoming ICMP packet can set the protocol field to 255 and match this socket, leading to FNHE cache changes. inner = IP(src="192.168.2.1", dst="8.8.8.8", proto=255)/Raw("TEST") pkt = IP(src="192.168.1.1", dst="192.168.2.1")/ICMP(type=3, code=4, nexthopmtu=576)/inner "man 7 raw" states: A protocol of IPPROTO_RAW implies enabled IP_HDRINCL and is able to send any IP protocol that is specified in the passed header. Receiving of all IP protocols via IPPROTO_RAW is not possible using raw sockets. Make sure we drop these malicious packets.
In the Linux kernel, the following vulnerability has been resolved: inet: RAW sockets using IPPROTO_RAW MUST drop incoming ICMP Yizhou Zhao reported that simply having one RAW socket on protocol IPPROTO_RAW (255) was dangerous. socket(AF_INET, SOCK_RAW, 255); A malicious incoming ICMP packet can set the protocol field to 255 and match this socket, leading to FNHE cache changes. inner = IP(src="192.168.2.1", dst="8.8.8.8", proto=255)/Raw("TEST") pkt = IP(src="192.168.1.1", dst="192.168.2.1")/ICMP(type=3, code=4, nexthopmtu=576)/inner "man 7 raw" states: A protocol of IPPROTO_RAW implies enabled IP_HDRINCL and is able to send any IP protocol that is specified in the passed header. Receiving of all IP protocols via IPPROTO_RAW is not possible using raw sockets. Make sure we drop these malicious packets.
In the Linux kernel, the following vulnerability has been resolved: i ...
In the Linux kernel, the following vulnerability has been resolved: inet: RAW sockets using IPPROTO_RAW MUST drop incoming ICMP Yizhou Zhao reported that simply having one RAW socket on protocol IPPROTO_RAW (255) was dangerous. socket(AF_INET, SOCK_RAW, 255); A malicious incoming ICMP packet can set the protocol field to 255 and match this socket, leading to FNHE cache changes. inner = IP(src="192.168.2.1", dst="8.8.8.8", proto=255)/Raw("TEST") pkt = IP(src="192.168.1.1", dst="192.168.2.1")/ICMP(type=3, code=4, nexthopmtu=576)/inner "man 7 raw" states: A protocol of IPPROTO_RAW implies enabled IP_HDRINCL and is able to send any IP protocol that is specified in the passed header. Receiving of all IP protocols via IPPROTO_RAW is not possible using raw sockets. Make sure we drop these malicious packets.
Уязвимость модулей net/ipv4/icmp.c и net/ipv6/icmp.c ядра операционной системы Linux, позволяющая нарушителю вызвать отказ в обслуживании
6.5 Medium
CVSS3