Linux Kernel up to 7.2-rc4 nexthop net/ipv4/nexthop.c nh_res_bucket_migrate extack uninitialized variable

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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9.5$0-$5k1.22+

Summaryinfo

A vulnerability, which was classified as very critical, was found in Linux Kernel up to 6.6.147/6.12.100/6.18.41/7.1.5/7.2-rc4. Affected by this vulnerability is the function nh_res_bucket_migrate of the file net/ipv4/nexthop.c of the component nexthop. Executing a manipulation of the argument extack can lead to uninitialized variable. This vulnerability is tracked as CVE-2026-64576. The attack can be launched remotely. No exploit exists.

Detailsinfo

A vulnerability has been found in Linux Kernel up to 6.6.147/6.12.100/6.18.41/7.1.5/7.2-rc4 and classified as very critical. This vulnerability affects the function nh_res_bucket_migrate of the file net/ipv4/nexthop.c of the component nexthop. The manipulation of the argument extack with an unknown input leads to a uninitialized variable vulnerability. The CWE definition for the vulnerability is CWE-457. The code uses a variable that has not been initialized, leading to unpredictable or unintended results. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: nexthop: initialize extack in nh_res_bucket_migrate() nh_res_bucket_migrate() passes an uninitialized netlink_ext_ack to call_nexthop_res_bucket_notifiers(). When nh_notifier_res_bucket_info_init() fails (e.g. the kzalloc returns -ENOMEM), the error is propagated back before any notifier sets extack._msg, and the error path formats the stale pointer with pr_err_ratelimited("%s\n", extack._msg). With CONFIG_INIT_STACK_NONE this dereferences uninitialized stack memory: Oops: general protection fault, probably for non-canonical address ... KASAN: maybe wild-memory-access in range [...] RIP: 0010:string (lib/vsprintf.c:730) vsnprintf (lib/vsprintf.c:2945) _printk (kernel/printk/printk.c:2504) nh_res_bucket_migrate (net/ipv4/nexthop.c:1816) nh_res_table_upkeep (net/ipv4/nexthop.c:1866) rtm_new_nexthop (net/ipv4/nexthop.c:3323) rtnetlink_rcv_msg (net/core/rtnetlink.c:7076) netlink_sendmsg (net/netlink/af_netlink.c:1900) Kernel panic - not syncing: Fatal exception Zero-initialize extack so _msg is NULL on error paths that never set it.

The advisory is available at git.kernel.org. This vulnerability was named CVE-2026-64576 since 07/19/2026. The exploitation appears to be easy. The attack can be initiated remotely. Technical details are known, but there is no available exploit. The structure of the vulnerability defines a possible price range of USD $0-$5k at the moment (estimation calculated on 08/05/2026).

Upgrading to version 6.6.148, 6.12.101, 6.18.42, 7.1.6 or 7.2-rc5 eliminates this vulnerability. Applying the patch c0936c131a71657afc635d0db2ab096d15d473e1/3081702ea5aca0aeed9c1ade8eadf6cde8db6b7d/d536bf205c71f700f6de2086038c3e1d77724715/18506d7263768d76ac8e057ba55a4d9da50aad66/6347c5314cee49f364aaf2e40ff15415a57a116e is able to eliminate this problem.

If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

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Version

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Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 9.9
VulDB Meta Temp Score: 9.5

VulDB Base Score: 9.9
VulDB Temp Score: 9.5
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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💳💳💳💳💳💳
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Uninitialized variable
CWE: CWE-457 / CWE-453
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

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

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Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.6.148/6.12.101/6.18.42/7.1.6/7.2-rc5
Patch: c0936c131a71657afc635d0db2ab096d15d473e1/3081702ea5aca0aeed9c1ade8eadf6cde8db6b7d/d536bf205c71f700f6de2086038c3e1d77724715/18506d7263768d76ac8e057ba55a4d9da50aad66/6347c5314cee49f364aaf2e40ff15415a57a116e

Timelineinfo

07/19/2026 CVE reserved
08/05/2026 +17 days Advisory disclosed
08/05/2026 +0 days VulDB entry created
08/05/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-64576 (🔒)
GCVE (CVE): GCVE-0-2026-64576
GCVE (VulDB): GCVE-100-386122

Entryinfo

Created: 08/05/2026 10:19
Changes: 08/05/2026 10:19 (61)
Complete: 🔍
Cache ID: 216::103

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