What’s Vulnerable › Vulnerabilities

CVE-2023-53987: ping: Fix potentail NULL deref for /proc/net/icmp.

• 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: 2025-12-24 · updated 2026-06-17

Description

In the Linux kernel, the following vulnerability has been resolved: ping: Fix potentail NULL deref for /proc/net/icmp. After commit dbca1596bbb0 ("ping: convert to RCU lookups, get rid of rwlock"), we use RCU for ping sockets, but we should use spinlock for /proc/net/icmp to avoid a potential NULL deref mentioned in the previous patch. Let's go back to using spinlock there. Note we can convert ping sockets to use hlist instead of hlist_nulls because we do not use SLAB_TYPESAFE_BY_RCU for ping sockets.

Affected products

• Linux kernel: from 5.19.2 before 5.20; 6.0 — fixed in 5.20, 6.3

How to fix

Upgrade to a fixed version: Linux kernel 5.20, 6.3. Check the vendor advisory for mitigations.

References

• https://git.kernel.org/stable/c/176cbb6da28f36506cc60a4bec4ab8df0c16713a
• https://git.kernel.org/stable/c/5a08a32e624908890aa0a2eb442bb6a7669891a8
• https://git.kernel.org/stable/c/ab5fb73ffa01072b4d8031cc05801fa1cb653bee

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