CVE-2026-43337

Description

In the Linux kernel, the following vulnerability has been resolved: drm/amd/display: Fix NULL pointer dereference in dcn401_init_hw() dcn401_init_hw() assumes that update_bw_bounding_box() is valid when entering the update path. However, the existing condition: ((!fams2_enable && update_bw_bounding_box) || freq_changed) does not guarantee this, as the freq_changed branch can evaluate to true independently of the callback pointer. This can result in calling update_bw_bounding_box() when it is NULL. Fix this by separating the update condition from the pointer checks and ensuring the callback, dc->clk_mgr, and bw_params are validated before use. Fixes the below: ../dc/hwss/dcn401/dcn401_hwseq.c:367 dcn401_init_hw() error: we previously assumed 'dc->res_pool->funcs->update_bw_bounding_box' could be null (see line 362) (cherry picked from commit 86117c5ab42f21562fedb0a64bffea3ee5fcd477)

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:6.12:-:*:*:*:*:*:* - VULNERABLE

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

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

Linux Kernel (具体受影响版本请参考Git内核提交记录10c13c1, 2d4a6f0等)

PoC / Exploit Code

⚠ For Security Research Only

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

python

#include <stdio.h>
#include <stdlib.h>

// Mock structures to simulate the kernel environment
struct dc {
    void *res_pool;
};

struct res_pool_funcs {
    void (*update_bw_bounding_box)(struct dc *dc);
};

struct res_pool {
    struct res_pool_funcs *funcs;
};

// Vulnerable function logic extracted from dcn401_init_hw
void vulnerable_logic(struct dc *dc, int fams2_enable, int freq_changed) {
    struct res_pool *pool = (struct res_pool *)dc->res_pool;
    void *update_bb = pool->funcs->update_bw_bounding_box;

    // The vulnerable condition
    if ((!fams2_enable && update_bb) || freq_changed) {
        printf("Condition met. Calling callback...\n");
        // This line causes NULL pointer dereference if update_bb is NULL but freq_changed is true
        ((void (*)(struct dc *))update_bb)(dc);
    }
}

int main() {
    struct dc dev_ctx = {0};
    struct res_pool pool_ctx = {0};
    struct res_pool_funcs funcs_ctx = {0};

    // Setup mock environment with NULL callback
    funcs_ctx.update_bw_bounding_box = NULL;
    pool_ctx.funcs = &funcs_ctx;
    dev_ctx.res_pool = &pool_ctx;

    printf("Triggering vulnerability with freq_changed=1 and callback=NULL\n");
    
    // Scenario: fams2_enable=0, freq_changed=1, callback=NULL
    // Logic: (!0 && NULL) || 1  -> (1 && 0) || 1 -> 0 || 1 -> 1 (True)
    // Result: NULL pointer dereference crash
    vulnerable_logic(&dev_ctx, 0, 1);

    return 0;
}

References

[1] CVE.org https://www.cve.org/CVERecord?id=CVE-2026-43337
[2] NVD NIST https://nvd.nist.gov/vuln/detail/CVE-2026-43337
[3] CVE Details https://www.cvedetails.com/cve/CVE-2026-43337/
[4] VulDB https://vuldb.com/cve/CVE-2026-43337
[5] https://git.kernel.org/stable/c/10c13c111d0d7f8e101c742feff264fc98e3f9f7
[6] https://git.kernel.org/stable/c/2d4a6f0702c5211e0be8b688c5fc24f082ec74d6
[7] https://git.kernel.org/stable/c/e927b36ae18b66b49219eaa9f46edc7b4fdbb25e

Raw JSON Data

JSON

{"cve": {"id": "CVE-2026-43337", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "published": "2026-05-08T14:16:43.517", "lastModified": "2026-05-15T19:56:32.423", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/amd/display: Fix NULL pointer dereference in dcn401_init_hw()\n\ndcn401_init_hw() assumes that update_bw_bounding_box() is valid when\nentering the update path. However, the existing condition:\n\n ((!fams2_enable && update_bw_bounding_box) || freq_changed)\n\ndoes not guarantee this, as the freq_changed branch can evaluate to true\nindependently of the callback pointer.\n\nThis can result in calling update_bw_bounding_box() when it is NULL.\n\nFix this by separating the update condition from the pointer checks and\nensuring the callback, dc->clk_mgr, and bw_params are validated before\nuse.\n\nFixes the below:\n../dc/hwss/dcn401/dcn401_hwseq.c:367 dcn401_init_hw() error: we previously assumed 'dc->res_pool->funcs->update_bw_bounding_box' could be null (see line 362)\n\n(cherry picked from commit 86117c5ab42f21562fedb0a64bffea3ee5fcd477)"}], "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-476"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.11.3", "versionEndExcluding": "6.18.22", "matchCriteriaId": "EB421B8C-E66F-451C-B0AF-8C2F85468489"}, {"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:6.12:-:*:*:*:*:*:*", "matchCriteriaId": "0E698080-7669-4132-8817-4C674EEBCE54"}, {"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/10c13c111d0d7f8e101c742feff264fc98e3f9f7", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/2d4a6f0702c5211e0be8b688c5fc24f082ec74d6", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/e927b36ae18b66b49219eaa9f46edc7b4fdbb25e", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}]}}