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CVE-2026-23300

Vulnérabilité non évaluée dans Linux (Linux)

CVSS 0.0 · Non évaluée
EPSS 0.1%
Linux•Linux•Versions : <=6.1.*, <=6.12.*, 493ced1ac47c48bb86d9d4e8e87df8592be85a0e, 0, 7.0, <21ec92774d1536f71bdc90b0e3d052eff99cf093, <607e68c1b7c5a30c795571be1906d716e989a644, <b299121e7453d23faddf464087dff513a495b4fc, 6.18.17, <b5062fc2150614c9ea8a611c2e0cb6e047ebfa3a, <=5.10.*, <=6.6.*, <=6.19.*, 5.15.203, 5.3, <=6.18.*, <5.3, <c11d7c56c2076ee9cd72004f1976fe0734df2ae9, 6.19.7, 6.1.167, <f7c9f8e3607440fe39300efbaf46cf7b5eecb23f, <=*, 5.10.253, <=5.15.*, 6.12.77, <b3b5a037d520afe3d5276e653bc0ff516bbda34c, <8650db85b4259d2885d2a80fbc2317ce24194133, 6.6.130

Description

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.

Gravité et risque d'exploitation

CVE-2026-23300 obtient un score CVSS de 0.0/10, soit une gravité non évaluée. Selon le modèle EPSS, la probabilité qu'elle soit exploitée dans les 30 prochains jours est de 0.13 %, ce qui la place devant 2.2 % des CVE référencées.

Que faire ?

  • Vérifiez si Linux (versions <=6.1.*, <=6.12.*, 493ced1ac47c48bb86d9d4e8e87df8592be85a0e, 0, 7.0, <21ec92774d1536f71bdc90b0e3d052eff99cf093, <607e68c1b7c5a30c795571be1906d716e989a644, <b299121e7453d23faddf464087dff513a495b4fc, 6.18.17, <b5062fc2150614c9ea8a611c2e0cb6e047ebfa3a, <=5.10.*, <=6.6.*, <=6.19.*, 5.15.203, 5.3, <=6.18.*, <5.3, <c11d7c56c2076ee9cd72004f1976fe0734df2ae9, 6.19.7, 6.1.167, <f7c9f8e3607440fe39300efbaf46cf7b5eecb23f, <=*, 5.10.253, <=5.15.*, 6.12.77, <b3b5a037d520afe3d5276e653bc0ff516bbda34c, <8650db85b4259d2885d2a80fbc2317ce24194133, 6.6.130) est présent sur votre parc.
  • Appliquez le correctif ou la version corrigée indiqués dans les références de l'éditeur.
  • À défaut de correctif, limitez l'exposition (filtrage réseau, désactivation du composant).
  • Automatisez la détection : les agents CVE Heimdall (gratuits, open source) corrèlent l'inventaire de vos serveurs avec la base CVE.

Références

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