CVE-2026-23399

#!/bin/bash # PoC Concept: Trigger nft_dynset memory leak # Requires vulnerable kernel version and nftables installed. # Add a table nft add table ip filter # Add a chain nft add chain ip filter input { type filter hook input priority 0 \; } # Create a set with dynamic update (dynset) # This attempts to add elements dynamically. # If the kernel fails to clone a 2nd stateful expr during an update, the leak occurs. # Reproducing requires inducing memory pressure or specific internal state. nft add rule ip filter input update @my_set { ip saddr limit rate 10/second } counter echo "Rule added. Under memory pressure or specific packet flow, this may trigger CVE-2026-23399." # Monitor kernel logs: dmesg | grep -i "unreferenced object"

{"cve": {"id": "CVE-2026-23399", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "published": "2026-03-28T08:15:56.720", "lastModified": "2026-04-27T14:16:30.913", "vulnStatus": "Modified", "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnf_tables: nft_dynset: fix possible stateful expression memleak in error path\n\nIf cloning the second stateful expression in the element via GFP_ATOMIC\nfails, then the first stateful expression remains in place without being\nreleased.\n\n   unreferenced object (percpu) 0x607b97e9cab8 (size 16):\n     comm \"softirq\", pid 0, jiffies 4294931867\n     hex dump (first 16 bytes on cpu 3):\n       00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00\n     backtrace (crc 0):\n       pcpu_alloc_noprof+0x453/0xd80\n       nft_counter_clone+0x9c/0x190 [nf_tables]\n       nft_expr_clone+0x8f/0x1b0 [nf_tables]\n       nft_dynset_new+0x2cb/0x5f0 [nf_tables]\n       nft_rhash_update+0x236/0x11c0 [nf_tables]\n       nft_dynset_eval+0x11f/0x670 [nf_tables]\n       nft_do_chain+0x253/0x1700 [nf_tables]\n       nft_do_chain_ipv4+0x18d/0x270 [nf_tables]\n       nf_hook_slow+0xaa/0x1e0\n       ip_local_deliver+0x209/0x330"}, {"lang": "es", "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nnf_tables: nft_dynset: corregir posible fuga de memoria de expresión con estado en la ruta de error\n\nSi la clonación de la segunda expresión con estado en el elemento a través de GFP_ATOMIC falla, entonces la primera expresión con estado permanece en su lugar sin ser liberada.\n\n   objeto sin referencia (por CPU) 0x607b97e9cab8 (tamaño 16):\n     comm 'softirq', pid 0, jiffies 4294931867\n     volcado hexadecimal (primeros 16 bytes en la CPU 3):\n       00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00\n     rastreo de pila (crc 0):\n       pcpu_alloc_noprof+0x453/0xd80\n       nft_counter_clone+0x9c/0x190 [nf_tables]\n       nft_expr_clone+0x8f/0x1b0 [nf_tables]\n       nft_dynset_new+0x2cb/0x5f0 [nf_tables]\n       nft_rhash_update+0x236/0x11c0 [nf_tables]\n       nft_dynset_eval+0x11f/0x670 [nf_tables]\n       nft_do_chain+0x253/0x1700 [nf_tables]\n       nft_do_chain_ipv4+0x18d/0x270 [nf_tables]\n       nf_hook_slow+0xaa/0x1e0\n       ip_local_deliver+0x209/0x330"}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H", "baseScore": 5.5, "baseSeverity": "MEDIUM", "attackVector": "LOCAL", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "HIGH"}, "exploitabilityScore": 1.8, "impactScore": 3.6}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-401"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.11.1", "versionEndExcluding": "6.12.78", "matchCriteriaId": "0618528B-8039-4E87-8695-397AE7D4B4E5"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.13", "versionEndExcluding": "6.18.20", "matchCriteriaId": "E5571059-6552-48E7-9BEF-3E358C387171"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.19", "versionEndExcluding": "6.19.10", "matchCriteriaId": "96D34333-38BE-4414-9E79-6EB764329581"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:5.11:-:*:*:*:*:*:*", "matchCriteriaId": "7AD3510E-E8FA-47F3-9AD5-D8EA4A2719D1"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:*", "matchCriteriaId": "F253B622-8837-4245-BCE5-A7BF8FC76A16"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:*", "matchCriteriaId": "4AE85AD8-4641-4E7C-A2F4-305E2CD9EE64"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc3:*:*:*:*:*:*", "matchCriteriaId": "F666C8D8-6538-46D4-B318-87610DE64C34"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc4:*:*:*:*:*:*", "matchCriteriaId": "02259FDA-961B-47BC-AE7F-93D7EC6E90C2"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc5:*:*:*:*:*:*", "matchCriteriaId": "58A9FEFF-C040-420D-8F0A-BFDAAA1DF258"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc6:*:*:*:*:*:*", "matchCriteriaId": "1D2315C0-D46F-4F85-9754-F9E5E11374A6"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc7:*:*:*:*:*:*", "matchCriteriaId": "512EE3A8-A590-4501-9A94-5D4B268D6138"}]}] ... (truncated)