Bug 2492324 (CVE-2026-53089)

Summary: CVE-2026-53089 kernel: bpf: Fix use-after-free in offloaded map/prog info fill
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: ---
Doc Text:
A flaw was found in the Linux kernel's BPF (Berkeley Packet Filter) subsystem. When querying information for an offloaded BPF map or program, a race condition can occur during network namespace destruction. This can lead to a use-after-free vulnerability, potentially causing a system crash or denial of service.
 Story Points: ---
Clone Of: Environment:
Last Closed: Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-06-24 18:05:48 UTC 
In the Linux kernel, the following vulnerability has been resolved:

bpf: Fix use-after-free in offloaded map/prog info fill

When querying info for an offloaded BPF map or program,
bpf_map_offload_info_fill_ns() and bpf_prog_offload_info_fill_ns()
obtain the network namespace with get_net(dev_net(offmap->netdev)).
However, the associated netdev's netns may be racing with teardown
during netns destruction. If the netns refcount has already reached 0,
get_net() performs a refcount_t increment on 0, triggering:

  refcount_t: addition on 0; use-after-free.

Although rtnl_lock and bpf_devs_lock ensure the netdev pointer remains
valid, they cannot prevent the netns refcount from reaching zero.

Fix this by using maybe_get_net() instead of get_net(). maybe_get_net()
uses refcount_inc_not_zero() and returns NULL if the refcount is already
zero, which causes ns_get_path_cb() to fail and the caller to return
-ENOENT -- the correct behavior when the netns is being destroyed.
Comment 1 Keith Grant 2026-06-26 18:06:33 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026062409-CVE-2026-53089-fdd8@gregkh/T