CVE-2026-53009: Linux ice Driver Double-Free Vulnerability – Local Privilege Escalation

Technical summary

CVE-2026-53009 is a use-after-free (CWE-416) and double-free (CWE-415) vulnerability in the Linux kernel's ice (Intel) network driver. The flaw occurs in ice_xmit_frame_ring() when ice_tso() or ice_tx_csum() fail during packet transmission setup. The error path frees the skb but fails to invalidate the corresponding tx_buf structure (still marked ICE_TX_BUF_SKB). While the next transmitted packet typically overwrites the stale reference, if the interface is brought down instead, ice_clean_tx_ring() -> ice_unmap_and_free_tx_buf() dereferences and frees the already-freed skb. The fix resets the tx_buf type to ICE_TX_BUF_EMPTY in error paths and relocates 'first' initialization earlier to ensure validity during linearization error handling.

Business impact

Systems running vulnerable Linux kernels with active ice driver workloads face local denial-of-service risk and potential privilege escalation. Affected environments include servers using Intel network adapters (particularly in cloud, datacenter, or high-availability scenarios where unexpected crashes impact availability). Remote exploitation is not possible; an attacker requires local access. The impact varies by workload: continuous network traffic may mask the bug through buffer overwriting, while light or intermittent traffic increases the window for triggering a double-free during interface shutdown.

Affected systems

The vulnerability affects Linux kernel versions incorporating the ice driver (Intel Ethernet Driver). Red Hat Enterprise Linux versions shipping affected kernels are in scope. Vendors and products confirmed: linux (linux_kernel), Red Hat (enterprise_linux). The vulnerability is not present in non-ice drivers or kernels without ice support. Verify your kernel version and whether the ice driver is loaded (lsmod | grep ice).

Exploitability

Exploitability requires local system access (PR:L in CVSS vector). No remote attack vector exists. An attacker must trigger packet transmission failures (via ice_tso() or ice_csum() failures) and then shut down the network interface, or rely on the natural window before the buffer is overwritten. The vulnerability is not trivial to trigger reliably in production but becomes more likely under specific packet types (large packets requiring TSO fragmentation) or constrained memory conditions. Public exploit code is not widely documented.

Remediation

Apply kernel updates from your Linux distributor that include the fix to ice_xmit_frame_ring(). Red Hat users should check RHSA advisories for patched RHEL kernel versions. The upstream Linux kernel fix involves resetting tx_buf type to ICE_TX_BUF_EMPTY in error paths and ensuring 'first' is initialized before potential error branches. Verify patch application by confirming ice driver version or kernel source commit hash matches the fix commit.

Patch guidance

1. Check your current kernel version: uname -r 2. Determine if ice driver is in use: lsmod | grep ice (if output is non-empty, you are affected if kernel is vulnerable) 3. Consult your Linux distributor's security advisories (Red Hat RHSA, Ubuntu USN, Debian DSA) for patched kernel versions 4. Schedule a kernel update and reboot during a maintenance window 5. After patching, verify the fix: grep -i 'ice.*tx_buf.*empty' /boot/config-$(uname -r) or inspect kernel source commit history for the double-free fix 6. If ice driver is not in use, risk is minimal; consider disabling it if not needed (modprobe -r ice).

Detection guidance

Monitor for kernel panic logs or KASAN (Kernel Address Sanitizer) warnings referencing ice driver, tx_buf, or double-free conditions. Enable kernel core dumps and examine them for ice_unmap_and_free_tx_buf or ice_xmit_frame_ring stack traces. Search syslog for 'use-after-free' or 'double-free' in ice driver context. On KASAN-enabled systems, look for '[ ] BUG: KASAN: use-after-free' messages. Correlate crashes with network interface state changes (ifdown events) or high packet transmission rates followed by interface shutdown. Intrusion detection: monitor system calls (clone, fork) from unprivileged processes immediately after network-related syscalls, though the primary risk is DoS rather than privilege escalation in most scenarios.

Why prioritize this

HIGH severity (CVSS 7.8) due to high impact scope (confidentiality, integrity, availability all high) combined with low attack complexity and local privilege requirement. While remote exploitation is impossible, the vulnerability affects core network functionality and can crash systems, impacting availability. Organizations with dense virtualization, containerized workloads, or multi-tenant systems where local attacker access is plausible should prioritize patching. Datacenters with Intel-based network adapters are at elevated risk. The 27-day window between publication (2026-06-24) and last modification (2026-07-22) suggests potential refinement; check vendor advisories for any related updates.

Risk score, explained

CVSS 3.1 score of 7.8 (HIGH) reflects: Attack Vector Local (no remote path, lowers score), Attack Complexity Low (any unprivileged user can trigger via network operations), Privileges Required Low (local user context), User Interaction None (automatic on specific conditions), and Scope Unchanged with High impact on Confidentiality, Integrity, and Availability (all processes on the system, including kernel, can crash or be affected). The score does not account for the CVSS v4 vector, real-world exploitability constraints (triggering double-free reliably requires specific packet patterns), or mitigation (unprivileged user restrictions in hardened kernels). For security teams, treat as HIGH priority in environments with local threat models; lower in air-gapped or single-tenant scenarios.

Frequently asked questions