CVE-2026-46037
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ICMP Reply Validation Bypass in Linux Kernel

Publication date: 2026-05-27

Last updated on: 2026-06-16

Assigner: kernel.org

Description
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.
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Meta Information
Published
2026-05-27
Last Modified
2026-06-16
Generated
2026-06-16
AI Q&A
2026-05-27
EPSS Evaluated
2026-06-15
NVD
CVE-2026-46037
EUVD
EUVD-2026-32418
Affected Vendors & Products
Showing 6 associated CPEs
Vendor Product Version / Range
linux linux_kernel From 6.7 (inc) to 6.12.86 (exc)
linux linux_kernel From 5.13 (inc) to 5.15.209 (exc)
linux linux_kernel From 5.16 (inc) to 6.1.175 (exc)
linux linux_kernel From 6.2 (inc) to 6.6.140 (exc)
linux linux_kernel From 6.13 (inc) to 6.18.27 (exc)
linux linux_kernel From 6.19 (inc) to 7.0.4 (exc)
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CWE ID Description
CWE-UNKNOWN
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Executive Summary

This vulnerability exists in the Linux kernel's handling of ICMP (Internet Control Message Protocol) messages. Specifically, it involves the validation of the reply type before using the icmp_pointers array. Extended echo replies use a reply type called ICMP_EXT_ECHOREPLY, which is outside the range covered by the icmp_pointers array that only handles traditional ICMP types. The vulnerability arises because the kernel might consult icmp_pointers[] for reply types outside its valid range, potentially leading to incorrect behavior or memory issues.

The fix involves avoiding the use of icmp_pointers[] for reply types outside the valid range and using a safer method (array_index_nospec()) for in-range lookups, ensuring normal ICMP replies behave as before.

Impact Analysis

If exploited, this vulnerability could cause the Linux kernel to behave incorrectly when processing certain ICMP extended echo replies. This might lead to unexpected kernel behavior, including potential memory safety issues or crashes, which could be leveraged by an attacker to disrupt system stability or cause denial of service.

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