CVE-2026-43493

Description

In the Linux kernel, the following vulnerability has been resolved: crypto: pcrypt - Fix handling of MAY_BACKLOG requests MAY_BACKLOG requests can return EBUSY. Handle them by checking for that value and filtering out EINPROGRESS notifications.

CVSS Details

CVSS Score

9.8

Severity

CRITICAL

CVSS Vector

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

Configurations (Affected Products)

No configuration data available.

Linux Kernel (修复提交 46271895ddfb1ba41f89f7e0dffbe9c2bcf7380a 之前的版本)

PoC / Exploit Code

⚠ For Security Research Only

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

python

/*
 * PoC for CVE-2026-43493 (Conceptual)
 * This module attempts to trigger the pcrypt MAY_BACKLOG handling issue.
 * Compile with: make -C /lib/modules/$(uname -r)/build M=$(pwd) modules
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/crypto.h>
#include <linux/err.h>

static int __init poc_init(void)
{
    struct crypto_aead *tfm;
    int ret;

    printk(KERN_INFO "CVE-2026-43493 PoC: Loading...\n");

    // Allocate a transform that uses pcrypt (e.g., aes-gcm)
    tfm = crypto_alloc_aead("pcrypt(aes-gcm)", 0, 0);
    if (IS_ERR(tfm)) {
        printk(KERN_INFO "CVE-2026-43493 PoC: Failed to allocate tfm\n");
        return PTR_ERR(tfm);
    }

    // In a real exploit scenario, one would flood the queue
    // to force EBUSY and observe the incorrect EINPROGRESS filtering.
    // This requires specific hardware or software driver conditions.
    
    printk(KERN_INFO "CVE-2026-43493 PoC: Triggering condition...\n");
    
    // Simulate payload trigger logic here
    // ret = trigger_backlog_condition(tfm);

    crypto_free_aead(tfm);
    return 0;
}

static void __exit poc_exit(void)
{
    printk(KERN_INFO "CVE-2026-43493 PoC: Unloading...\n");
}

module_init(poc_init);
module_exit(poc_exit);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("PoC for CVE-2026-43493");

References

[1] CVE.org https://www.cve.org/CVERecord?id=CVE-2026-43493
[2] NVD NIST https://nvd.nist.gov/vuln/detail/CVE-2026-43493
[3] CVE Details https://www.cvedetails.com/cve/CVE-2026-43493/
[4] VulDB https://vuldb.com/cve/CVE-2026-43493
[5] https://git.kernel.org/stable/c/46271895ddfb1ba41f89f7e0dffbe9c2bcf7380a
[6] https://git.kernel.org/stable/c/77d55bc8675ee851ed639dc9be77325a8024cf67
[7] https://git.kernel.org/stable/c/915b692e6cb723aac658c25eb82c58fd81235110
[8] https://git.kernel.org/stable/c/9f1cbca178c03188e201ed175251372149bb25f2
[9] https://git.kernel.org/stable/c/eb34e243df57e32f4c08fa191f3602ea19076276

Raw JSON Data

JSON

{"cve": {"id": "CVE-2026-43493", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "published": "2026-05-19T12:16:19.020", "lastModified": "2026-05-20T17:16:23.517", "vulnStatus": "Received", "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ncrypto: pcrypt - Fix handling of MAY_BACKLOG requests\n\nMAY_BACKLOG requests can return EBUSY.  Handle them by checking\nfor that value and filtering out EINPROGRESS notifications."}], "metrics": {"cvssMetricV31": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "baseScore": 9.8, "baseSeverity": "CRITICAL", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH"}, "exploitabilityScore": 3.9, "impactScore": 5.9}]}, "references": [{"url": "https://git.kernel.org/stable/c/46271895ddfb1ba41f89f7e0dffbe9c2bcf7380a", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/77d55bc8675ee851ed639dc9be77325a8024cf67", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/915b692e6cb723aac658c25eb82c58fd81235110", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/9f1cbca178c03188e201ed175251372149bb25f2", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/eb34e243df57e32f4c08fa191f3602ea19076276", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}]}}