Yüksek CVSS 7.8

CVE-2026-23111: Linux Kernel: serbest bırakılmış belleğin kullanımı

Yayın: 13 Şubat 2026 17:16 · Güncelleme: 6 Kasım 2026 10:18

Açıklama (NVD)

In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_tables: fix inverted genmask check in nft_map_catchall_activate() nft_map_catchall_activate() has an inverted element activity check compared to its non-catchall counterpart nft_mapelem_activate() and compared to what is logically required. nft_map_catchall_activate() is called from the abort path to re-activate catchall map elements that were deactivated during a failed transaction. It should skip elements that are already active (they don't need re-activation) and process elements that are inactive (they need to be restored). Instead, the current code does the opposite: it skips inactive elements and processes active ones. Compare the non-catchall activate callback, which is correct: nft_mapelem_activate(): if (nft_set_elem_active(ext, iter->genmask)) return 0; /* skip active, process inactive */ With the buggy catchall version: nft_map_catchall_activate(): if (!nft_set_elem_active(ext, genmask)) continue; /* skip inactive, process active */ The consequence is that when a DELSET operation is aborted, nft_setelem_data_activate() is never called for the catchall element. For NFT_GOTO verdict elements, this means nft_data_hold() is never called to restore the chain->use reference count. Each abort cycle permanently decrements chain->use. Once chain->use reaches zero, DELCHAIN succeeds and frees the chain while catchall verdict elements still reference it, resulting in a use-after-free. This is exploitable for local privilege escalation from an unprivileged user via user namespaces + nftables on distributions that enable CONFIG_USER_NS and CONFIG_NF_TABLES. Fix by removing the negation so the check matches nft_mapelem_activate(): skip active elements, process inactive ones.

Özet bilgiler

Ürün: Linux Linux Kernel
CVSS v3.1: 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS: %0,52 (yüzdelik 44)
CWE: CWE-416
Yama: Mevcut

Etkilenen sürümler

Ürün	Başlangıç	Bitiş	Düzeltildi
linux-linux-kernel	4.19.316	—	4.20
linux-linux-kernel	5.4.262	—	5.5
linux-linux-kernel	5.10.188	—	5.11
linux-linux-kernel	5.15.121	—	5.15.200
linux-linux-kernel	6.1.36	—	6.1.163
linux-linux-kernel	6.3.10	—	6.4
linux-linux-kernel	6.4.1	—	6.6.124
linux-linux-kernel	6.7	—	6.12.70
linux-linux-kernel	6.13	—	6.18.10
linux-linux-kernel	6.4	6.4	—
linux-linux-kernel	6.19	6.19	—
linux-linux-kernel	6.19	6.19	—
linux-linux-kernel	6.19	6.19	—
linux-linux-kernel	6.19	6.19	—
linux-linux-kernel	6.19	6.19	—
linux-linux-kernel	6.19	6.19	—
linux-linux-kernel	6.19	6.19	—
linux-linux-kernel	6.19	6.19	—

Kaynaklar

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