What’s Vulnerable › Vulnerabilities

CVE-2026-98031: nexthop: Initialize extack in remove_nh_grp_entry()

• Severity: unknown
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-09-25 · updated 2026-10-19

Description

In the Linux kernel, the following vulnerability has been resolved: nexthop: Initialize extack in remove_nh_grp_entry() remove_nh_grp_entry() prints the extack message when a listener fails to replace the reduced nexthop group. However, extack is not initialized and listeners are not required to set a message when returning an error. Neither netdevsim nor mlxsw do so when an allocation fails, resulting in the dereference of an uninitialized stack pointer. Fix by zero-initializing extack, as was done in commit 6347c5314cee ("nexthop: initialize extack in nh_res_bucket_migrate()").

Affected products

• Linux kernel: 5.11 — fixed in 7.3

How to fix

Upgrade to a fixed version: Linux kernel 7.3. Check the vendor advisory for mitigations.

References

• https://git.kernel.org/stable/c/030c878eaedf0449e2b5401a0a0146d0afcc645e
• https://git.kernel.org/stable/c/17acbcd4c5a6ca3dd3f9e52eb203c9175bde609a
• https://git.kernel.org/stable/c/35d9ec61466109ef0c2de87067338d929f629527
• https://git.kernel.org/stable/c/5bd9e4e7cdaa03879e9b73b12ab52cceb1edd55b
• https://git.kernel.org/stable/c/704319510af2179cf03955747d714ab291075c25
• https://git.kernel.org/stable/c/d643cea4248668dc493c513aa7cbc6505eb1a4a9
• https://git.kernel.org/stable/c/d80677ad7aa5bebfccfd58caa4852b65abe70561

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