Orta CVSS 5.5
CVE-2026-23300: Linux Kernel: NULL işaretçi başvurusu
Açıklama (NVD)
In the Linux kernel, the following vulnerability has been resolved: net: ipv6: fix panic when IPv4 route references loopback IPv6 nexthop When a standalone IPv6 nexthop object is created with a loopback device (e.g., "ip -6 nexthop add id 100 dev lo"), fib6_nh_init() misclassifies it as a reject route. This is because nexthop objects have no destination prefix (fc_dst=::), causing fib6_is_reject() to match any loopback nexthop. The reject path skips fib_nh_common_init(), leaving nhc_pcpu_rth_output unallocated. If an IPv4 route later references this nexthop, __mkroute_output() dereferences NULL nhc_pcpu_rth_output and panics. Simplify the check in fib6_nh_init() to only match explicit reject routes (RTF_REJECT) instead of using fib6_is_reject(). The loopback promotion heuristic in fib6_is_reject() is handled separately by ip6_route_info_create_nh(). After this change, the three cases behave as follows: 1. Explicit reject route ("ip -6 route add unreachable 2001:db8::/64"): RTF_REJECT is set, enters reject path, skips fib_nh_common_init(). No behavior change. 2. Implicit loopback reject route ("ip -6 route add 2001:db8::/32 dev lo"): RTF_REJECT is not set, takes normal path, fib_nh_common_init() is called. ip6_route_info_create_nh() still promotes it to reject afterward. nhc_pcpu_rth_output is allocated but unused, which is harmless. 3. Standalone nexthop object ("ip -6 nexthop add id 100 dev lo"): RTF_REJECT is not set, takes normal path, fib_nh_common_init() is called. nhc_pcpu_rth_output is properly allocated, fixing the crash when IPv4 routes reference this nexthop.
Özet bilgiler
- Ürün
- Linux Linux Kernel
- CVSS v3.1
- 5.5
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H - EPSS
- %0,13 (yüzdelik 3)
- CWE
- CWE-476
- Yama
- Mevcut
Etkilenen sürümler
| Ürün | Başlangıç | Bitiş | Düzeltildi |
|---|---|---|---|
| linux-linux-kernel | 5.3 | — | 5.10.253 |
| linux-linux-kernel | 5.11 | — | 5.15.203 |
| linux-linux-kernel | 5.16 | — | 6.1.167 |
| linux-linux-kernel | 6.2 | — | 6.6.130 |
| linux-linux-kernel | 6.7 | — | 6.12.77 |
| linux-linux-kernel | 6.13 | — | 6.18.17 |
| linux-linux-kernel | 6.19 | — | 6.19.7 |
| linux-linux-kernel | 7.0 | 7.0 | — |
| linux-linux-kernel | 7.0 | 7.0 | — |