CVE-2026-43034

Description

In the Linux kernel, the following vulnerability has been resolved: bnxt_en: set backing store type from query type bnxt_hwrm_func_backing_store_qcaps_v2() stores resp->type from the firmware response in ctxm->type and later uses that value to index fixed backing-store metadata arrays such as ctx_arr[] and bnxt_bstore_to_trace[]. ctxm->type is fixed by the current backing-store query type and matches the array index of ctx->ctx_arr. Set ctxm->type from the current loop variable instead of depending on resp->type. Also update the loop to advance type from next_valid_type in the for statement, which keeps the control flow simpler for non-valid and unchanged entries.

CVSS Details

CVSS Score

5.5

Severity

MEDIUM

CVSS Vector

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

Configurations (Affected Products)

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

cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:* - VULNERABLE

cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:* - VULNERABLE

cpe:2.3:o:linux:linux_kernel:7.0:rc3:*:*:*:*:*:* - VULNERABLE

Linux Kernel (Versions prior to commits 29732b6, 4ee9371, c8d53b7)

PoC / Exploit Code

⚠ For Security Research Only

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

python

/*
 * PoC Concept for CVE-2026-43034
 * This is a conceptual demonstration. Triggering this requires specific hardware
 * (Broadcom NetXtreme-C/E) and interaction with the bnxt_en driver.
 * The vulnerability is triggered during the backing store query capabilities phase.
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/netdevice.h>

// Conceptual trigger function
void trigger_vulnerability(struct net_device *dev) {
    // In a real scenario, this would involve sending specific HWRM commands
    // or causing the driver to re-initialize/query backing store types
    // where the firmware response (resp->type) does not match the expected loop index.
    
    printk(KERN_INFO "Attempting to trigger bnxt_en backing store query logic...\n");
    
    // The actual trigger happens inside bnxt_hwrm_func_backing_store_qcaps_v2
    // when processing the response from firmware.
    // If an attacker can influence the firmware response or force a specific state,
    // they might cause ctxm->type to be used as an invalid array index.
}

int init_module(void) {
    printk(KERN_INFO "CVE-2026-43034 PoC Loaded\n");
    return 0;
}

void cleanup_module(void) {
    printk(KERN_INFO "CVE-2026-43034 PoC Unloaded\n");
}

MODULE_LICENSE("GPL");

References

[1] CVE.org https://www.cve.org/CVERecord?id=CVE-2026-43034
[2] NVD NIST https://nvd.nist.gov/vuln/detail/CVE-2026-43034
[3] CVE Details https://www.cvedetails.com/cve/CVE-2026-43034/
[4] VulDB https://vuldb.com/cve/CVE-2026-43034
[5] https://git.kernel.org/stable/c/29732b68a6816a815d58e9ab229844c23617e1e0
[6] https://git.kernel.org/stable/c/4ee937107d52f9e5c350e4b5e629760e328b3d9f
[7] https://git.kernel.org/stable/c/c8d53b70166d1dc463ef42adb7293e1a770822c7

Raw JSON Data

JSON

{"cve": {"id": "CVE-2026-43034", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "published": "2026-05-01T15:16:48.037", "lastModified": "2026-05-08T18:41:52.870", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbnxt_en: set backing store type from query type\n\nbnxt_hwrm_func_backing_store_qcaps_v2() stores resp->type from the\nfirmware response in ctxm->type and later uses that value to index\nfixed backing-store metadata arrays such as ctx_arr[] and\nbnxt_bstore_to_trace[].\n\nctxm->type is fixed by the current backing-store query type and matches\nthe array index of ctx->ctx_arr. Set ctxm->type from the current loop\nvariable instead of depending on resp->type.\n\nAlso update the loop to advance type from next_valid_type in the for\nstatement, which keeps the control flow simpler for non-valid and\nunchanged entries."}], "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": "NVD-CWE-noinfo"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.8", "versionEndExcluding": "6.18.22", "matchCriteriaId": "4504ACF8-60DF-4391-A1A9-01874A74C6F8"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.19", "versionEndExcluding": "6.19.12", "matchCriteriaId": "0A2B9540-02D5-41B4-B16A-82AF66FD4F36"}, {"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"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/29732b68a6816a815d58e9ab229844c23617e1e0", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/4ee937107d52f9e5c350e4b5e629760e328b3d9f", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/c8d53b70166d1dc463ef42adb7293e1a770822c7", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}]}}