Linux Kernel up to 6.18.49/7.2.3 IPv6 RPL SRH Reception ipv6_rpl_srh_rcv idev null pointer dereference

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7.2	$0-$5k	0.00+

Summaryinfo

A vulnerability has been found in Linux Kernel up to 6.18.49/7.2.3 and classified as critical. This vulnerability affects the function ipv6_rpl_srh_rcv of the component IPv6 RPL SRH Reception. Performing a manipulation of the argument idev results in null pointer dereference. This vulnerability is reported as CVE-2026-89561. The attack is possible to be carried out remotely. No exploit exists. The affected component should be upgraded.

Detailsinfo

A vulnerability classified as critical has been found in Linux Kernel up to 6.18.49/7.2.3. This affects the function ipv6_rpl_srh_rcv of the component IPv6 RPL SRH Reception. The manipulation of the argument idev with an unknown input leads to a null pointer dereference vulnerability. CWE is classifying the issue as CWE-476. A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit. This is going to have an impact on availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: ipv6: rpl: fix NULL dereference of idev in ipv6_rpl_srh_rcv() ipv6_rpl_srh_rcv() dereferences idev from __in6_dev_get() without a NULL check when reading idev->cnf.rpl_seg_enabled. When the device's MTU drops below IPV6_MIN_MTU, addrconf_ifdown() clears dev->ip6_ptr through RCU_INIT_POINTER(). A packet that passed the idev check in ip6_rcv_core() can then reach ipv6_rpl_srh_rcv() with dev->ip6_ptr already NULL. Reproduced by flooding the receiving interface with ping6 traffic while flapping its MTU between 1500 and 1200: BUG: KASAN: null-ptr-deref in ipv6_rpl_srh_rcv+0xb3/0x1070 Read of size 4 at addr 00000000000006b4 by task ping6/394 CPU: 2 UID: 0 PID: 394 Comm: ping6 Not tainted 7.2.0-rc7-micro-vm-dev-00095-g24ef02f934ee #240 PREEMPT(full) Call Trace: <IRQ> kasan_report+0xc6/0x100 ipv6_rpl_srh_rcv+0xb3/0x1070 ip6_protocol_deliver_rcu+0x759/0x9a0 ip6_input_finish+0xa8/0x1b0 ip6_input+0xe1/0x490 ipv6_rcv+0x33d/0x460 __netif_receive_skb_one_core+0xd6/0x130 process_backlog+0x2cc/0xa00 __napi_poll.constprop.0+0x56/0x270 net_rx_action+0x327/0x730 handle_softirqs+0x11e/0x630 do_softirq+0xb3/0xf0 </IRQ> Both ipv6_rpl_srh_rcv() and ipv6_srh_rcv() are called only from ipv6_rthdr_rcv(), which already has an idev lookup. Fix the NULL dereference on the RPL path by checking idev in ipv6_rthdr_rcv(), before it calls either function. The callees take idev as an argument and no longer call __in6_dev_get(), so the packet is now dropped in one place, with SKB_DROP_REASON_IPV6DISABLED on both paths.

It is possible to read the advisory at git.kernel.org. This vulnerability is uniquely identified as CVE-2026-89561 since 09/11/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. Technical details of the vulnerability are known, but there is no available exploit. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 09/12/2026).

Upgrading to version 6.18.50, 7.2.4 or 7.3-rc1 eliminates this vulnerability. Applying the patch 63f50e9f90d0287ad66a0955ebfc2d3a9c044a1c/eab3a917cdcb182542a3aac6a0d2d30659ca9821/f826df95332c07380206dbd54178b6eefb311aba is able to eliminate this problem. The best possible mitigation is suggested to be upgrading to the latest version.

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Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 6.18.0
• 6.18.1
• 6.18.2
• 6.18.3
• 6.18.4
• 6.18.5
• 6.18.6
• 6.18.7
• 6.18.8
• 6.18.9
• 6.18.10
• 6.18.11
• 6.18.12
• 6.18.13
• 6.18.14
• 6.18.15
• 6.18.16
• 6.18.17
• 6.18.18
• 6.18.19
• 6.18.20
• 6.18.21
• 6.18.22
• 6.18.23
• 6.18.24
• 6.18.25
• 6.18.26
• 6.18.27
• 6.18.28
• 6.18.29
• 6.18.30
• 6.18.31
• 6.18.32
• 6.18.33
• 6.18.34
• 6.18.35
• 6.18.36
• 6.18.37
• 6.18.38
• 6.18.39
• 6.18.40
• 6.18.41
• 6.18.42
• 6.18.43
• 6.18.44
• 6.18.45
• 6.18.46
• 6.18.47
• 6.18.48
• 6.18.49
• 7.2.0
• 7.2.1
• 7.2.2
• 7.2.3

License

• open-source

Website

• Vendor: https://www.kernel.org/

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒
• 🔒

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.5
VulDB Meta Temp Score: 7.2

VulDB Base Score: 7.5
VulDB Temp Score: 7.2
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AV	AC	Au	C	I	A
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳

Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock

VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Null pointer dereference
CWE: CWE-476 / CWE-404
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.18.50/7.2.4/7.3-rc1
Patch: 63f50e9f90d0287ad66a0955ebfc2d3a9c044a1c/eab3a917cdcb182542a3aac6a0d2d30659ca9821/f826df95332c07380206dbd54178b6eefb311aba

Timelineinfo

09/11/2026 CVE reserved
09/11/2026 +0 days VulDB entry created
09/12/2026 +0 days Advisory disclosed
09/12/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-89561 (🔒)
GCVE (CVE): GCVE-0-2026-89561
GCVE (VulDB): GCVE-100-402867

Entryinfo

Created: 09/12/2026 01:17
Changes: 09/12/2026 01:17 (60)
Complete: 🔍
Cache ID: 216::103

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Discussion

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