CVE-2026-64190 Linux vulnerability
In the Linux kernel, the following vulnerability has been resolved: net: team: fix NULL pointer dereference in team_xmit during mode change __team_change_mode() clears team->ops with memset() before restoring safe dummy handlers via team_adjust_ops(). A concurrent team_xmit() running under RCU on another CPU can read team->ops.transmit during this window and call a NULL function pointer, crashing the kernel. The race requires a mode change (CAP_NET_ADMIN) concurrent with transmit on the team device. BUG: kernel NULL pointer dereference, address: 0000000000000000 Oops: 0010 [#1] SMP KASAN NOPTI RIP: 0010:0x0 Call Trace: team_xmit (drivers/net/team/team_core.c:1853) dev_hard_start_xmit (net/core/dev.c:3904) __dev_queue_xmit (net/core/dev.c:4871) packet_sendmsg (net/packet/af_packet.c:3109) __sys_sendto (net/socket.c:2265) The original code assumed that no ports means no traffic, so mode changes could freely memset()/memcpy() the ops. AF_PACKET with forced carrier breaks that assumption. Prevent the race instead of making it safe: replace memset()/memcpy() with per-field updates that never touch transmit or receive. Those two handlers are managed solely by team_adjust_ops(), which already installs dummies when tx_en_port_count == 0 (always true during mode change since no ports are present). WRITE_ONCE/READ_ONCE prevent store/load tearing on the handler pointers. synchronize_net() before exit_op() drains in-flight readers that may still reference old mode state from before port removal switched the handlers to dummies.
Browse Linux security risksQuick answer
Linux should be reviewed and updated if it matches the affected versions. The recommended fix is to apply the vendor-supported patched version or the mitigation steps below, then retest the public website with Fixnx.
Who is affected
Affected versions
- < 03e9405c518c4d61f28079492f252d6d4e2bac5c
- < 25fe708bbc59289d3d1ea4b126fbc1b460a072a5
- 3.3
Fixed versions
- 6.18.35
- 7.1
How to fix it
CVE-2026-64190 affects Linux and involves denial of service. A remote or untrusted peer may consume excessive resources or crash the affected service. Prioritize deployments that process untrusted input, expose the affected feature, or hold sensitive data. Upgrade Linux to 6.18.35, 7.1 or a later vendor-supported fixed release.
- Inventory every deployment, device, package, plugin, container, build, and environment that uses Linux.
- Compare the installed version with the recorded affected range: < 03e9405c518c4d61f28079492f252d6d4e2bac5c, < 25fe708bbc59289d3d1ea4b126fbc1b460a072a5, 3.3.
- Upgrade Linux to 6.18.35, 7.1 or a later vendor-supported fixed release.
- Until patched, limit untrusted files and peers, apply resource limits, and isolate the affected parser or service.
- Review configuration, roles, tokens, network paths, and exposed endpoints connected to Linux; remove access that is not required.
- Review application, system, proxy, and audit logs for requests and behavior linked to the affected feature and CVE.
- If exploitation is suspected, isolate affected assets, preserve evidence, rotate exposed credentials or keys, restore trusted data, and rebuild compromised systems before returning them to service.
Scan now. Google sign-in is only needed to unlock fix guidance.
Verify the fix
- Confirm every affected asset now runs the fixed vendor-supported release or has the documented mitigation for CVE-2026-64190 in place.
- Use a safe regression test to confirm the affected denial of service path no longer produces the vulnerable behavior.
- Confirm temporary access controls, endpoint restrictions, network blocks, and least-privilege settings remain effective after the update.
- Review post-remediation logs and rerun Fixnx plus the relevant package, dependency, firmware, browser, or product-specific security check.
- Document affected assets, versions, changes, validation evidence, reviewed logs, and any credential rotation, cleanup, or replacement completed.
Related categories
Related security risks
More published guidance from the same primary category.
Trusted references
FAQ
What is affected by CVE-2026-64190?
Linux versions listed as affected should be reviewed: < 03e9405c518c4d61f28079492f252d6d4e2bac5c, < 25fe708bbc59289d3d1ea4b126fbc1b460a072a5, 3.3.
What should I fix first?
Start with internet-facing sites, admin panels, login flows, plugins, themes, modules, packages, and systems that process user-controlled input or sensitive data.
How do I confirm the fix worked?
Apply the patched version or mitigation, clear caches where relevant, retest the affected workflow, and run a new Fixnx scan to verify public website exposure signals.
How are Fixnx security risk categories chosen?
Fixnx keeps one canonical risk page and assigns only broad, relevant categories such as ecosystem, technology area, or vulnerability class.