Описание
In the Linux kernel, the following vulnerability has been resolved:
ipv6: icmp: clear skb2->cb[] in ip6_err_gen_icmpv6_unreach()
Sashiko AI-review observed:
In ip6_err_gen_icmpv6_unreach(), the skb is an outer IPv4 ICMP error packet
where its cb contains an IPv4 inet_skb_parm. When skb is cloned into skb2
and passed to icmp6_send(), it uses IP6CB(skb2).
IP6CB interprets the IPv4 inet_skb_parm as an inet6_skb_parm. The cipso
offset in inet_skb_parm.opt directly overlaps with dsthao in inet6_skb_parm
at offset 18.
If an attacker sends a forged ICMPv4 error with a CIPSO IP option, dsthao
would be a non-zero offset. Inside icmp6_send(), mip6_addr_swap() is called
and uses ipv6_find_tlv(skb, opt->dsthao, IPV6_TLV_HAO).
This would scan the inner, attacker-controlled IPv6 packet starting at that
offset, potentially returning a fake TLV without checking if the remaining
packet length can hold the full 18-byte struct ipv6_destopt_hao.
Could mip6_addr_swap() then perform a 16-byte swap that extends past the end
of the packet data into skb_shared_info?
Should the cb array also be cleared in ip6_err_gen_icmpv6_unreach() and
ip6ip6_err() to prevent this?
This patch implements the first suggestion.
I am not sure if ip6ip6_err() needs to be changed.
A separate patch would be better anyway.
A flaw was found in the Linux kernel's IPv6 ICMP error generation. A remote attacker could send a specially crafted IPv4 ICMP error packet with a Common Internet Protocol Security Option (CIPSO) IP option. This could lead to incorrect handling of packet control block data when generating an IPv6 ICMP error, potentially causing an out-of-bounds memory access. This memory corruption could result in information disclosure or a denial of service.
Меры по смягчению последствий
Mitigation for this issue is either not available or the currently available options do not 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 | Not affected | ||
| Red Hat Enterprise Linux 7 | kernel | Not affected | ||
| Red Hat Enterprise Linux 7 | kernel-rt | Not affected | ||
| Red Hat Enterprise Linux 9 | kernel-rt | Affected | ||
| Red Hat Enterprise Linux 10 | kernel | Fixed | RHSA-2026:30129 | 25.06.2026 |
| Red Hat Enterprise Linux 10 | kpatch-patch | Fixed | RHSA-2026:55618 | 17.08.2026 |
| Red Hat Enterprise Linux 10.0 Extended Update Support | kernel | Fixed | RHSA-2026:24343 | 08.06.2026 |
| Red Hat Enterprise Linux 8 | kernel-rt | Fixed | RHSA-2026:25120 | 10.06.2026 |
| Red Hat Enterprise Linux 8 | kernel | Fixed | RHSA-2026:25121 | 10.06.2026 |
| Red Hat Enterprise Linux 8 | kpatch-patch | Fixed | RHSA-2026:55762 | 17.08.2026 |
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Дополнительная информация
Статус:
7.3 High
CVSS3
Связанные уязвимости
In the Linux kernel, the following vulnerability has been resolved: ipv6: icmp: clear skb2->cb[] in ip6_err_gen_icmpv6_unreach() Sashiko AI-review observed: In ip6_err_gen_icmpv6_unreach(), the skb is an outer IPv4 ICMP error packet where its cb contains an IPv4 inet_skb_parm. When skb is cloned into skb2 and passed to icmp6_send(), it uses IP6CB(skb2). IP6CB interprets the IPv4 inet_skb_parm as an inet6_skb_parm. The cipso offset in inet_skb_parm.opt directly overlaps with dsthao in inet6_skb_parm at offset 18. If an attacker sends a forged ICMPv4 error with a CIPSO IP option, dsthao would be a non-zero offset. Inside icmp6_send(), mip6_addr_swap() is called and uses ipv6_find_tlv(skb, opt->dsthao, IPV6_TLV_HAO). This would scan the inner, attacker-controlled IPv6 packet starting at that offset, potentially returning a fake TLV without checking if the remaining packet length can hold the full 18-byte struct ipv6_destopt_hao. Could mip6_addr_swap() then perform a 16-byte swap that e...
In the Linux kernel, the following vulnerability has been resolved: ipv6: icmp: clear skb2->cb[] in ip6_err_gen_icmpv6_unreach() Sashiko AI-review observed: In ip6_err_gen_icmpv6_unreach(), the skb is an outer IPv4 ICMP error packet where its cb contains an IPv4 inet_skb_parm. When skb is cloned into skb2 and passed to icmp6_send(), it uses IP6CB(skb2). IP6CB interprets the IPv4 inet_skb_parm as an inet6_skb_parm. The cipso offset in inet_skb_parm.opt directly overlaps with dsthao in inet6_skb_parm at offset 18. If an attacker sends a forged ICMPv4 error with a CIPSO IP option, dsthao would be a non-zero offset. Inside icmp6_send(), mip6_addr_swap() is called and uses ipv6_find_tlv(skb, opt->dsthao, IPV6_TLV_HAO). This would scan the inner, attacker-controlled IPv6 packet starting at that offset, potentially returning a fake TLV without checking if the remaining packet length can hold the full 18-byte struct ipv6_destopt_hao. Could mip6_addr_swap() then
In the Linux kernel, the following vulnerability has been resolved: i ...
In the Linux kernel, the following vulnerability has been resolved: ipv6: icmp: clear skb2->cb[] in ip6_err_gen_icmpv6_unreach() Sashiko AI-review observed: In ip6_err_gen_icmpv6_unreach(), the skb is an outer IPv4 ICMP error packet where its cb contains an IPv4 inet_skb_parm. When skb is cloned into skb2 and passed to icmp6_send(), it uses IP6CB(skb2). IP6CB interprets the IPv4 inet_skb_parm as an inet6_skb_parm. The cipso offset in inet_skb_parm.opt directly overlaps with dsthao in inet6_skb_parm at offset 18. If an attacker sends a forged ICMPv4 error with a CIPSO IP option, dsthao would be a non-zero offset. Inside icmp6_send(), mip6_addr_swap() is called and uses ipv6_find_tlv(skb, opt->dsthao, IPV6_TLV_HAO). This would scan the inner, attacker-controlled IPv6 packet starting at that offset, potentially returning a fake TLV without checking if the remaining packet length can hold the full 18-byte struct ipv6_destopt_hao. Could mip6_addr_swap() t...
Уязвимость функции ip6_err_gen_icmpv6_unreach() модуля net/ipv6/icmp.c ядра операционной системы Linux, позволяющая нарушителю получить несанкционированный доступ к защищаемой информации или вызвать отказ в обслуживании
7.3 High
CVSS3