CVE-2026-72342

What the bug is

mlx5e_hv_vhca_stats_create() registers the stats agent through mlx5_hv_vhca_agent_create(). The helper publishes the agent in hv_vhca->agents[type] under agents_lock and immediately schedules an asynchronous control invalidation on the HV VHCA workqueue before returning to mlx5e. The asynchronous invalidation invokes the control agent's invalidate callback, which reads the hypervisor control block and forwards the command to mlx5e_hv_vhca_stats_control(). That callback may either: - call cancel_delayed_work_sync(&priv->stats_agent.work), or - call queue_delayed_work(priv->wq, &sagent->work, sagent->delay). However, the delayed_work and priv->stats_agent.agent are only initialized after mlx5_hv_vhca_agent_create() returns to mlx5e: agent = mlx5_hv_vhca_agent_create(...); /* publish + invalidate */ ... priv->stats_agent.agent = agent; /* too late */ INIT_DELAYED_WORK(&priv->stats_agent.work, ...); /* too late */ If the asynchronous control path runs before the two assignments above, it can: - Operate on an uninitialized delayed_work whose timer.function is NULL. queue_delayed_work() calls add_timer() unconditionally, so when the timer expires the timer softirq invokes a NULL function pointer. - Re-initialize the timer later through INIT_DELAYED_WORK() while the timer is already enqueued in the timer wheel, corrupting the hlist (entry.pprev cleared while the previous bucket node still points at this entry). - When the worker eventually runs, mlx5e_hv_vhca_stats_work() reads sagent->agent (NULL) and dereferences it inside mlx5_hv_vhca_agent_write(). Fix this by: - Initializing priv->stats_agent.work before invoking mlx5_hv_vhca_agent_create(), so the work is always in a valid state when the control callback observes it. - Adding a struct mlx5_hv_vhca_agent **ctx_update out-parameter to mlx5_hv_vhca_agent_create(). The helper writes the agent pointer to *ctx_update before publishing into hv_vhca->agents[] and triggering the agents_update flow, so any callback subsequently invoked from that flow already sees a valid priv->stats_agent.agent. This avoids having the control callback participate in agent initialization. While at it, access priv->stats_agent.agent with READ_ONCE()/WRITE_ONCE() for the cross-CPU access with the worker, and clear priv->stats_agent.buf on the agent_create() failure path.

Where it lives

The fix touches these files. If the subsystem is one you do not use, the practical exposure is lower, though the package is still the vulnerable one.

drivers/net/ethernet/mellanox/mlx5/core/en/hv_vhca_stats.c
drivers/net/ethernet/mellanox/mlx5/core/lib/hv_vhca.c
drivers/net/ethernet/mellanox/mlx5/core/lib/hv_vhca.h

What this is

MELLANOX MLX5 core VPI driverMAINTAINERS section matched on drivers/net/ethernet/mellanox/mlx5/core/ · netdev@vger.kernel.org · Maintained

Show whether Debian builds this, per release

Not established. This site could not find the build rule for the affected file in the kernel trees Debian ships, so it has no answer about whether Debian compiles this code. Read that as unknown, never as absent.

• bookworm, trixie, forky, sid?

?

not established - no Makefile entry for the affected file

Where a release above reads "not established", no build rule for the affected file was found in that release's kernel tree. That is a gap in this lookup, not a finding that the code is absent.

From the configuration Debian publishes for every kernel flavour it builds. It covers only the architectures Debian ships a linux-config package for, and nothing about a kernel you built yourself. Debian's own status above stays authoritative about the source package.MAINTAINERS

Signals

Published

2026-08-15 (2 months ago)source

CVSS

8.4 high
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:Hsource recompute it

Attack vector

local (AV:L)source

EPSS

0.20%, higher than 8.6% of all CVEssource

CISA KEV

not listedthe KEV catalogue

Debian urgency

not yet assignedsource

Subsystem

drivers/net

Upstream fixes

The versions the CNA records as introducing and fixing this, and the commit for each. source

Introduced	Fixed in	Commit
5.4	6.1.178	b0fd6d3bb061
5.4	6.6.145	24c77044cdfc
5.4	6.12.97	e8fc3304cb67
5.4	6.18.40	60fddda7207d
5.4	7.1.5	f5677797b094
5.4	7.2	89b25b5f46f4