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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CTI Interest Score
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8.3$0-$5k0.00

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 08/10/2026).

The vulnerability scanner Nessus provides a plugin with the ID 332760 (Linux Distros Unpatched Vulnerability : CVE-2026-64576), which helps to determine the existence of the flaw in a target environment.

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.

The vulnerability is also documented in the vulnerability database at Tenable (332760). If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 8.5
VulDB Meta Temp Score: 8.3

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

CNA Base Score: 7.1
CNA Vector (Linux): 🔒

CVSSv2info

AVACAuCIA
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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: Partially
Local: Yes
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 332760
Nessus Name: Linux Distros Unpatched Vulnerability : CVE-2026-64576

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
08/10/2026 +5 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
Updated: 08/10/2026 02:14
Changes: 08/05/2026 10:19 (61), 08/06/2026 05:56 (2), 08/10/2026 02:14 (11)
Complete: 🔍
Cache ID: 216::103

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

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