high CVSS 8.2 EPSS 0.63%

CVE-2026-46037·Kernel vulnerability

In the Linux kernel, the following vulnerability has been resolved: ipv4: icmp: validate reply type before using icmp_pointers Extended echo replies use ICMP_EXT_ECHOREPLY as the outbound reply type. That value is outside the range covered by icmp_pointers[], which only describes the traditional ICMP types up to NR_ICMP_TYPES. Avoid consulting icmp_pointers[] for reply types outside that range, and use array_index_nospec() for the remaining in-range lookup. Normal ICMP replies keep their existing behavior unchanged.

Severity
high
Software
Kernel
Fixed in
7.0.4
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 0.63% — higher than 49% 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-2026-46037 scores 8.2 on CVSS, so a successful attack would be serious — but at 0.63%, 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: 6.19

Until: 7.0.4

Fixed in: 7.0.4

How to fix this CVE

Update your Linux kernel to version 7.0.4 or later to patch the ICMP reply type validation vulnerability. This fix prevents out-of-bounds memory access when the kernel processes extended ICMP echo replies by validating reply types before accessing the icmp_pointers array. Systems running kernel versions 6.19 through 7.0.3 should prioritize this update.

sudo dnf update kernel kernel-devel

Defensia detects this vulnerability

How to check if you are affected

  1. Step 1: Check kernel version with `uname -r` and compare against affected range 6.19-7.0.3
  2. Step 2: Verify ICMP processing is enabled with `cat /proc/sys/net/ipv4/icmp_echo_ignore_all` (0 = enabled, vulnerable if in range)
  3. Step 3: Search kernel logs for out-of-bounds access attempts with `sudo journalctl -S -1h | grep -i 'kernel.*out.of.bounds\|icmp'`
  4. Step 4: After patching, confirm new kernel is loaded with `uname -r` and verify it shows version 7.0.4 or later

FAQ

What is CVE-2026-46037?

A memory safety vulnerability in the Linux kernel's ICMP handling where extended echo reply types bypass bounds validation, allowing potential out-of-bounds array access during ICMP packet processing.

Is CVE-2026-46037 being actively exploited?

No, there is no evidence of active exploitation in the wild, and no public exploits have been released for this vulnerability.

What versions of Kernel are affected by CVE-2026-46037?

Linux kernel versions 6.19 through 7.0.3 are affected; version 7.0.4 and later contain the fix.

How do I check if my server is vulnerable to CVE-2026-46037?

Run `uname -r` and check if the version falls between 6.19 and 7.0.3; if so, your system requires the update to 7.0.4 or later.

Does Defensia detect CVE-2026-46037?

Yes — Defensia's CVE advisory scanner compares installed package versions against the NVD database. If Kernel is installed on a monitored server, CVE-2026-46037 will appear in your dashboard with remediation steps.

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References

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