CVSS 7.8 · High EPSS 0,52%
Kerentanan Use After Free pada linux kernel. Skor CVSS 3.1 7.8 (High) menurut 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.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
· uraikan di kalkulator | Vendor | Produk | Versi terdampak |
|---|---|---|
| linux | linux kernel | Versi 4.19.316 hingga sebelum 4.20 |
| linux | linux kernel | Versi 5.4.262 hingga sebelum 5.5 |
| linux | linux kernel | Versi 5.10.188 hingga sebelum 5.11 |
| linux | linux kernel | Versi 5.15.121 hingga sebelum 5.15.200 |
| linux | linux kernel | Versi 6.1.36 hingga sebelum 6.1.163 |
| linux | linux kernel | Versi 6.3.10 hingga sebelum 6.4 |
| linux | linux kernel | Versi 6.4.1 hingga sebelum 6.6.124 |
| linux | linux kernel | Versi 6.7 hingga sebelum 6.12.70 |
| linux | linux kernel | Versi 6.13 hingga sebelum 6.18.10 |
| linux | linux kernel | Versi 6.4 |
| linux | linux kernel | Versi 6.19 rc1 |
| linux | linux kernel | Versi 6.19 rc2 |
| linux | linux kernel | Versi 6.19 rc3 |
| linux | linux kernel | Versi 6.19 rc4 |
| linux | linux kernel | Versi 6.19 rc5 |
| linux | linux kernel | Versi 6.19 rc6 |
| linux | linux kernel | Versi 6.19 rc7 |
| linux | linux kernel | Versi 6.19 rc8 |