high CVSS 7.8 EPSS <0.1%

CVE-2024-26952·Kernel vulnerability

In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix potencial out-of-bounds when buffer offset is invalid I found potencial out-of-bounds when buffer offset fields of a few requests is invalid. This patch set the minimum value of buffer offset field to ->Buffer offset to validate buffer length.

Severity
high
Software
Kernel
Fixed in
6.8.3
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 9% 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-2024-26952 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: 6.8

Until: 6.8.3

Fixed in: 6.8.3

How to fix this CVE

Update your Linux kernel to version 6.8.3 or later to patch the buffer offset validation vulnerability in the ksmbd subsystem. This vulnerability allows local attackers with standard user privileges to read sensitive kernel memory or trigger a denial of service by providing malformed SMB requests with invalid buffer offsets. Systems running kernel versions 6.8 through 6.8.2 should prioritize this kernel update immediately.

sudo dnf update kernel kernel-devel

Defensia detects this vulnerability

How to check if you are affected

  1. Step 1: Check your installed kernel version by running `uname -r` and compare against the affected range (6.8.0 to 6.8.2)
  2. Step 2: Verify ksmbd is enabled in your kernel configuration by checking `grep -i CONFIG_SMB_SERVER /boot/config-$(uname -r)` — if it returns 'y' or 'm', the vulnerable component is present
  3. Step 3: Search system logs for SMB protocol errors using `journalctl -u smbd | grep -i "buffer\|offset\|out-of-bounds" --ignore-case` or check `/var/log/syslog` for ksmbd crash warnings
  4. Step 4: After applying the kernel update and rebooting, run `uname -r` to confirm the new version is 6.8.3 or higher

FAQ

What is CVE-2024-26952?

CVE-2024-26952 is a buffer offset validation flaw in the Linux kernel's ksmbd (SMB server) implementation that allows local attackers to trigger out-of-bounds memory access by sending specially crafted SMB requests with invalid buffer offset values.

Is CVE-2024-26952 being actively exploited?

No, CVE-2024-26952 is not listed on the CISA Known Exploited Vulnerabilities catalog and no public exploits are currently available, though the high CVSS score (7.8) indicates the flaw poses a significant local attack risk.

What versions of Kernel are affected by CVE-2024-26952?

Linux kernel versions 6.8.0 through 6.8.2 are affected. The vulnerability is patched in kernel version 6.8.3 and later.

How do I check if my server is vulnerable to CVE-2024-26952?

Run `uname -r` to check your kernel version — if it reports 6.8.0, 6.8.1, or 6.8.2, you are vulnerable. Additionally, confirm ksmbd is enabled with `grep CONFIG_SMB_SERVER /boot/config-$(uname -r)`.

Does Defensia detect CVE-2024-26952?

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-2024-26952 will appear in your dashboard with remediation steps.

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References

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