CVE-2021-47397

What it is

In the Linux kernel, the following vulnerability has been resolved: sctp: break out if skb_header_pointer returns NULL in sctp_rcv_ootb We should always check if skb_header_pointer's return is NULL before using it, otherwise it may cause null-ptr-deref, as syzbot reported: KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] RIP: 0010:sctp_rcv_ootb net/sctp/input.c:705 [inline] RIP: 0010:sctp_rcv+0x1d84/0x3220 net/sctp/input.c:196 Call Trace: <IRQ> sctp6_rcv+0x38/0x60 net/sctp/ipv6.c:1109 ip6_protocol_deliver_rcu+0x2e9/0x1ca0 net/ipv6/ip6_input.c:422 ip6_input_finish+0x62/0x170 net/ipv6/ip6_input.c:463 NF_HOOK include/linux/netfilter.h:307 [inline] NF_HOOK include/linux/netfilter.h:301 [inline] ip6_input+0x9c/0xd0 net/ipv6/ip6_input.c:472 dst_input include/net/dst.h:460 [inline] ip6_rcv_finish net/ipv6/ip6_input.c:76 [inline] NF_HOOK include/linux/netfilter.h:307 [inline] NF_HOOK include/linux/netfilter.h:301 [inline] ipv6_rcv+0x28c/0x3c0 net/ipv6/ip6_input.c:297

At a glance

Exploitability

Can be exploited over the network without logging in. High risk of service disruption.

Exploit odds

0.8% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2024-05-21 15:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-08-04 10:17 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 0.8% in the next 30 days (EPSS).
• Severity: 7.5 HIGH (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2024-05-21 15:15 UTC

Last modified

2026-08-04 10:17 UTC

Exploit probability

0.8% · EPSS, next 30 days

Weakness

CWE-476 · NULL pointer dereference

Record status

Modified

Affected

• Linux Kernel < 4.14.249
• Linux Kernel < 4.19.209
• Linux Kernel < 5.4.151
• Linux Kernel < 5.10.71
• Linux Kernel < 5.14.10
• Linux Kernel 5.15

Attack profile CVSS 3.1 · 7.5

Attack vector

Network

Complexity

Low

Privileges needed

None

User interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2021-47397.md and follow it. Check whether this project is affected by CVE-2021-47397. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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