CVE-2026-23392

Description

In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_tables: release flowtable after rcu grace period on error Call synchronize_rcu() after unregistering the hooks from error path, since a hook that already refers to this flowtable can be already registered, exposing this flowtable to packet path and nfnetlink_hook control plane. This error path is rare, it should only happen by reaching the maximum number hooks or by failing to set up to hardware offload, just call synchronize_rcu(). There is a check for already used device hooks by different flowtable that could result in EEXIST at this late stage. The hook parser can be updated to perform this check earlier to this error path really becomes rarely exercised. Uncovered by KASAN reported as use-after-free from nfnetlink_hook path when dumping hooks.

CVSS Details

CVSS Score

7.8

Severity

HIGH

CVSS Vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Configurations (Affected Products)

cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* - VULNERABLE

Linux Kernel (修复补丁发布前的版本)

PoC / Exploit Code

⚠ For Security Research Only

The following code is for security research and authorized testing only.

python

/*
 * PoC for CVE-2026-23392: Trigger UAF in nf_tables
 * This PoC attempts to create a flowtable configuration
 * that hits the error path and triggers the use-after-free.
 */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <linux/netlink.h>
#include <linux/netfilter/nf_tables.h>

void trigger_uaf() {
    // Create a netlink socket to interact with nf_tables
    int sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_NETFILTER);
    if (sock < 0) {
        perror("socket");
        return;
    }

    struct sockaddr_nl addr;
    memset(&addr, 0, sizeof(addr));
    addr.nl_family = AF_NETFLOW;

    // Setup flowtable creation message
    // Intentionally trigger conditions that lead to the error path
    // e.g., hook overlap or hardware offload failure simulation
    
    // 1. Create a table
    // 2. Create a flowtable with specific device hooks
    // 3. Attempt to create another conflicting flowtable or force error
    
    // 4. Dump hooks via nfnetlink to trigger the race condition
    // while the RCU grace period hasn't passed.
    
    printf("Attempting to trigger CVE-2026-23392...\n");
    // ... (Netlink message construction omitted for brevity)
    // Ideally, this forces the kernel into the error path
    // where nf_tables_flowtable_destroy is called without synchronize_rcu.
    
    close(sock);
}

int main() {
    trigger_uaf();
    return 0;
}

References

[1] CVE.org https://www.cve.org/CVERecord?id=CVE-2026-23392
[2] NVD NIST https://nvd.nist.gov/vuln/detail/CVE-2026-23392
[3] CVE Details https://www.cvedetails.com/cve/CVE-2026-23392/
[4] VulDB https://vuldb.com/cve/CVE-2026-23392
[5] https://git.kernel.org/stable/c/7e3955b282eae20d61c75e499c75eade51c20060
[6] https://git.kernel.org/stable/c/adee3436ccd29f1e514c028899e400cbc6d84065
[7] https://git.kernel.org/stable/c/c8092edb9a11f20f95ccceeb9422b7dd0df337bd
[8] https://git.kernel.org/stable/c/d2632de96ccb066e0131ad1494241b9c281c60b8
[9] https://git.kernel.org/stable/c/d73f4b53aaaea4c95f245e491aa5eeb8a21874ce
[10] https://git.kernel.org/stable/c/e78a2dcc7cfb87b64a631441ca7681492b347ef6

Raw JSON Data

JSON

{"cve": {"id": "CVE-2026-23392", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "published": "2026-03-25T11:16:39.873", "lastModified": "2026-04-24T18:39:15.767", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nf_tables: release flowtable after rcu grace period on error\n\nCall synchronize_rcu() after unregistering the hooks from error path,\nsince a hook that already refers to this flowtable can be already\nregistered, exposing this flowtable to packet path and nfnetlink_hook\ncontrol plane.\n\nThis error path is rare, it should only happen by reaching the maximum\nnumber hooks or by failing to set up to hardware offload, just call\nsynchronize_rcu().\n\nThere is a check for already used device hooks by different flowtable\nthat could result in EEXIST at this late stage. The hook parser can be\nupdated to perform this check earlier to this error path really becomes\nrarely exercised.\n\nUncovered by KASAN reported as use-after-free from nfnetlink_hook path\nwhen dumping hooks."}, {"lang": "es", "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nnetfilter: nf_tables: liberar la tabla de flujos después del período de gracia de RCU en caso de error\n\nLlamar a synchronize_rcu() después de desregistrar los hooks de la ruta de error, ya que un hook que ya se refiere a esta tabla de flujos puede estar ya registrado, exponiendo esta tabla de flujos a la ruta de paquetes y al plano de control de nfnetlink_hook.\n\nEsta ruta de error es rara, solo debería ocurrir al alcanzar el número máximo de hooks o al fallar la configuración para la descarga de hardware; simplemente llamar a synchronize_rcu().\n\nExiste una comprobación para hooks de dispositivo ya utilizados por una tabla de flujos diferente que podría resultar en EEXIST en esta etapa tardía. El analizador de hooks puede ser actualizado para realizar esta comprobación antes, para que esta ruta de error realmente se ejercite raramente.\n\nDescubierto por KASAN, reportado como uso después de liberación desde la ruta de nfnetlink_hook al volcar los hooks."}], "metrics": {"cvssMetricV31": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH", "attackVector": "LOCAL", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH"}, "exploitabilityScore": 1.8, "impactScore": 5.9}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-416"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.16.1", "versionEndExcluding": "6.1.167", "matchCriteriaId": "7A5DC72A-93EB-4A9B-B708-F1AF1B80B184"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.2", "versionEndExcluding": "6.6.130", "matchCriteriaId": "C57BB918-DF28-46B3-94F7-144176841267"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.7", "versionEndExcluding": "6.12.78", "matchCriteriaId": "28D591F5-B196-4CC9-905C-DC80F116E7A8"}, {"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:4.16:-:*:*:*:*:*:*", "matchCriteriaId": "F60469AF-0A23-41D3-BC6A-C0D9A45A2CBC"}, {"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 ... 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