high CVSS 7.8 EPSS <0.1%

CVE-2024-53057·Kernel vulnerability

In the Linux kernel, the following vulnerability has been resolved: net/sched: stop qdisc_tree_reduce_backlog on TC_H_ROOT In qdisc_tree_reduce_backlog, Qdiscs with major handle ffff: are assumed to be either root or ingress. This assumption is bogus since it's valid to create egress qdiscs with major handle ffff: Budimir Markovic found that for qdiscs like DRR that maintain an active class list, it will cause a UAF with a dangling class pointer. In 066a3b5b2346, the concern was to avoid iterating over the ingress qdisc since its parent is itself. The proper fix is to stop when parent TC_H_ROOT is reached because the only way to retrieve ingress is when a hierarchy which does not contain a ffff: major handle call into qdisc_lookup with TC_H_MAJ(TC_H_ROOT). In the scenario where major ffff: is an egress qdisc in any of the tree levels, the updates will also propagate to TC_H_ROOT, which then the iteration must stop. net/sched/sch_api.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

Severity
high
Software
Kernel
Fixed in
6.11.7
Published

How likely is exploitation

FIRST's Exploit Prediction Scoring System puts the probability of this CVE being exploited in the next 30 days at <0.1% — higher than 3% of all published CVEs. EPSS is an independent forecast of exploitation, not a severity rating: it says nothing about how much damage a successful attack does, which is what a CVSS score measures.

Read the two together. CVE-2024-53057 scores 7.8 on CVSS, so a successful attack would be serious — but at <0.1%, almost nobody is currently attempting it. That is a different situation from a flaw under mass exploitation, and it is usually the difference between patching on your next maintenance window and patching tonight.

Affected versions

From: 6.7

Until: 6.11.7

Fixed in: 6.11.7

How to fix this CVE

Update your Linux kernel to version 6.11.7 or later to resolve a use-after-free vulnerability in the qdisc traffic control subsystem. The vulnerability occurs when the kernel incorrectly handles egress queuing discipline objects with certain handle values, leading to memory corruption. Apply this critical patch immediately, especially on systems running kernels 6.7 through 6.11.6.

sudo dnf update kernel kernel-devel

Defensia detects this vulnerability

How to check if you are affected

  1. Step 1: Check installed kernel version with `uname -r` and compare against 6.11.7 (vulnerable if 6.7.x through 6.11.6)
  2. Step 2: Verify qdisc configuration with `tc qdisc show` to identify active traffic control rules using DRR or similar disciplines
  3. Step 3: Monitor dmesg and /var/log/kern.log for UAF warnings: `dmesg | grep -i 'use-after-free\|UAF\|qdisc' and tail -f /var/log/kern.log | grep -i 'qdisc\|backlog'`
  4. Step 4: After patching, reboot the system with `sudo reboot` and confirm new kernel loaded via `uname -r`, then verify qdisc operations remain stable over 24 hours

FAQ

What is CVE-2024-53057?

CVE-2024-53057 is a use-after-free vulnerability in the Linux kernel's traffic control (qdisc) subsystem that occurs when the kernel mishandles egress queue discipline objects with major handle 0xffff:, causing memory corruption and potential denial of service.

Is CVE-2024-53057 being actively exploited?

No, CVE-2024-53057 is not listed in CISA's Known Exploited Vulnerabilities catalog and no public exploits are currently available. However, it should still be patched promptly due to its high severity rating.

What versions of Kernel are affected by CVE-2024-53057?

Linux kernel versions 6.7 through 6.11.6 are vulnerable. The vulnerability is patched in kernel 6.11.7 and later versions.

How do I check if my server is vulnerable to CVE-2024-53057?

Run `uname -r` to check your kernel version. If it reports a version between 6.7.0 and 6.11.6 (inclusive), your system is vulnerable and requires immediate patching.

Does Defensia detect CVE-2024-53057?

Yes — Defensia's CVE advisory scanner compares installed package versions against the NVD database. If the Linux kernel is installed on a monitored server, CVE-2024-53057 will appear in your dashboard with remediation steps.

Related Kernel CVEs

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CVE-2026-64268CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: RDMA/siw: bound Read Response placement to the RREAD length In drivers/infiniband/sw/siw/siw_qp_rx.c, siw_proc_rresp() places each inbound Read Response DDP segment at sge->laddr + wqe->processed and then accumulates wqe->processed, but it never checks the running total against the sink buffer length on continuation segments. siw_check_sge() resolves and validates the sink memory only on the first fragment (the if (!*mem) branch), and siw_rresp_check_ntoh() compares the cumulative length against wqe->bytes only on the final segment (the !frx->more_ddp_segs guard). A connected siw peer that answers an outstanding RREAD with Read Response segments that keep the DDP Last flag clear, carrying more total payload than the RREAD requested, drives wqe->processed past the validated sink buffer; the next siw_rx_data() call writes out of bounds at sge->laddr + wqe->processed. siw runs iWARP over ordinary routable TCP, so the peer is the remote end of an established RDMA connection and needs no local privilege. Bound every segment before placement, exactly as siw_proc_send() and siw_proc_write() already do for their tagged and untagged paths, and terminate the connection with a base-or-bounds DDP error when the Read Response would overrun the sink buffer. This is the second receive-path length fix for this file. A separate change rejects an MPA FPDU length that underflows the per-fragment remainder in the header decode; that guard does not cover this case, because here each individual segment length is self-consistent and only the accumulated placement offset overruns the buffer.
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CVE-2026-53384CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: serial: 8250_dw: unregister 8250 port if clk_notifier_register() fails dw8250_probe() registers the 8250 port via serial8250_register_8250_port() and then, if the device has a clock, registers a clock notifier. If clk_notifier_register() fails, probe returns the error but leaves the 8250 port registered. The matching serial8250_unregister_port() lives in dw8250_remove(), which is not called when probe fails, so the port slot stays occupied until the device is rebound or the system is rebooted. The devm-allocated driver data is freed while the port still references it (via the saved private_data and serial_in/serial_out callbacks), so any access to that port slot before a rebind is a use-after-free hazard. Unregister the port on the clk_notifier_register() error path.

References

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