Linux Kernel up to 7.2-rc2 mlx5e net/mlx5e mlx5e_hv_vhca_stats_create stats_nch/max_nch double free

CVSS Meta Temp Score
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CTI Interest Score
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9.5$5k-$25k0.48+

Summaryinfo

A vulnerability was found in Linux Kernel up to 7.2-rc2 and classified as very critical. Affected by this vulnerability is the function mlx5e_hv_vhca_stats_create of the file net/mlx5e of the component mlx5e. Executing a manipulation of the argument stats_nch/max_nch can lead to double free. This vulnerability is registered as CVE-2026-72343. It is possible to launch the attack remotely. No exploit is available.

Detailsinfo

A vulnerability was found in Linux Kernel up to 7.2-rc2. It has been declared as very critical. This vulnerability affects the function mlx5e_hv_vhca_stats_create of the file net/mlx5e of the component mlx5e. The manipulation of the argument stats_nch/max_nch with an unknown input leads to a double free vulnerability. The CWE definition for the vulnerability is CWE-415. The product calls free() twice on the same memory address, potentially leading to modification of unexpected memory locations. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: net/mlx5e: Fix HV VHCA stats zero-sized buffer allocation mlx5e_hv_vhca_stats_create() is called from mlx5e_nic_enable(), before mlx5e_open(). At that point priv->stats_nch is still zero, because it is only ever incremented in mlx5e_channel_stats_alloc(), which is reached only from mlx5e_open_channel(). mlx5e_hv_vhca_stats_buf_size() therefore returns 0, and kvzalloc(0, GFP_KERNEL) returns ZERO_SIZE_PTR ((void *)16) rather than NULL. The "if (!buf)" guard does not catch this, and mlx5e_hv_vhca_stats_create() completes "successfully" with priv->stats_agent.buf set to ZERO_SIZE_PTR. Once channels are opened (priv->stats_nch > 0) and the hypervisor enables stats reporting, mlx5e_hv_vhca_stats_work() recomputes buf_len using the new non-zero stats_nch and calls memset(buf, 0, buf_len) on ZERO_SIZE_PTR, faulting at address 0x10. Allocate the buffer based on priv->max_nch, which is set in mlx5e_priv_init() and is the upper bound on stats_nch: - Add a separate helper mlx5e_hv_vhca_stats_buf_max_size() that returns sizeof(per_ring_stats) * max(max_nch, stats_nch), and use it for the kvzalloc() in mlx5e_hv_vhca_stats_create(). - Keep mlx5e_hv_vhca_stats_buf_size() (which returns based on stats_nch) for the worker's active payload size, so the wire format (block->rings = stats_nch) and the amount of data filled by mlx5e_hv_vhca_fill_stats() are unchanged. The max(max_nch, stats_nch) guard handles the rare case where mlx5e_attach_netdev() recomputes max_nch downward across a detach/resume cycle while priv->stats_nch persists (mlx5e_detach_netdev does not call mlx5e_priv_cleanup, so stats_nch is only reset when the netdev is destroyed). Without the guard, the worker could compute buf_len from stats_nch and overrun the smaller buffer allocated based on the reduced max_nch. Allocating a non-zero buffer also makes the kvzalloc() failure path in mlx5e_hv_vhca_stats_create() reachable for the first time: it returns early without (re)creating the agent. Clear priv->stats_agent.{agent,buf} in mlx5e_hv_vhca_stats_destroy() after freeing them, so that if a later create() bails out on this path, a subsequent teardown does not double-free the stale agent/buffer left from a previous enable/disable cycle. This mirrors the existing mlx5e pattern of preallocating arrays of size max_nch (e.g. priv->channel_stats) and lazily populating entries up to stats_nch on demand.

The advisory is shared for download at git.kernel.org. This vulnerability was named CVE-2026-72343 since 08/09/2026. The exploitation appears to be easy. The attack can be initiated remotely. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $5k-$25k (estimation calculated on 08/15/2026).

Upgrading to version 6.1.178, 6.6.145, 6.12.97, 6.18.40, 7.1.5 or 7.2-rc3 eliminates this vulnerability. Applying the patch 3b3a552cf88e10bb7bda88b29cf1fd8267043d50/5b927dcec5f1087942bf123a82e64a3f66475f01/22c1d5ecccf92c849bdca1556179aafc95794baf/420aabb32da4381d8d7cdcaa6a77fad9eaceb0a4/abc4c56427f144c96b2827a4db3b90eb5b7349a2/25f6b929c7e379cbea7cb8caa67b49b2d1efae17 is able to eliminate this problem.

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Productinfo

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

Exploitinginfo

Class: Double free
CWE: CWE-415 / CWE-119
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 6.1.178/6.6.145/6.12.97/6.18.40/7.1.5/7.2-rc3
Patch: 3b3a552cf88e10bb7bda88b29cf1fd8267043d50/5b927dcec5f1087942bf123a82e64a3f66475f01/22c1d5ecccf92c849bdca1556179aafc95794baf/420aabb32da4381d8d7cdcaa6a77fad9eaceb0a4/abc4c56427f144c96b2827a4db3b90eb5b7349a2/25f6b929c7e379cbea7cb8caa67b49b2d1efae17

Timelineinfo

08/09/2026 CVE reserved
08/15/2026 +6 days Advisory disclosed
08/15/2026 +0 days VulDB entry created
08/15/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-72343 (🔒)
GCVE (CVE): GCVE-0-2026-72343
GCVE (VulDB): GCVE-100-390940

Entryinfo

Created: 08/15/2026 16:29
Changes: 08/15/2026 16:29 (61)
Complete: 🔍
Cache ID: 216::103

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