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Linux Kernel EUVDEUVD-2026-59322

| CVE-2026-72423 HIGH
2026-08-15 Linux GHSA-x2j2-wxw5-pjr8
Information Disclosure Linux Red Hat Suse
8.8
CVSS 3.1 · Vendor: Linux
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Severity by source

Vendor (Linux) PRIMARY
8.8 HIGH
AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
vuln.today AI
8.2 HIGH

Conntrack BPF kfuncs require CAP_BPF or CAP_SYS_ADMIN on default-hardened kernels, warranting PR:H; kernel memory corruption crosses the process security boundary, justifying S:C.

3.1 AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
4.0 AV:L/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
SUSE
3.4 MEDIUM
AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:L/A:L
Red Hat
5.5 MEDIUM
qualitative

Primary rating from Vendor (Linux).

CVSS VectorVendor: Linux

Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

Lifecycle Timeline

5
Analysis Generated
Aug 17, 2026 - 09:19 vuln.today
CVSS changed
Aug 17, 2026 - 06:22 NVD
8.8 (HIGH)
Patch available
Aug 15, 2026 - 07:20 EUVD
CVE Published
Aug 15, 2026 - 05:56 cve.org
HIGH 8.8
CVE Published
Aug 15, 2026 - 05:56 cve.org
UNKNOWN (no severity yet)

DescriptionCVE.org

In the Linux kernel, the following vulnerability has been resolved:

bpf: Guard conntrack opts error writes

The conntrack lookup and allocation kfuncs take an opts pointer together with an opts__sz argument. The verifier checks only the memory range described by opts__sz, but the wrappers unconditionally write opts->error whenever the internal lookup or allocation helper returns an error.

For an invalid size smaller than the end of opts->error, that write can land outside the verifier-checked range. Keep returning NULL for invalid arguments, but only report the error through opts->error when the supplied size includes the field.

This preserves error reporting for the supported 12-byte and 16-byte layouts, and for other invalid sizes that still include opts->error.

AnalysisAI

Out-of-bounds kernel memory write in the Linux kernel BPF conntrack kfuncs allows a local attacker with BPF access to corrupt memory outside the verifier-enforced boundary. The BPF verifier constrains accessible memory using the caller-supplied opts__sz argument, but the conntrack wrapper functions unconditionally write to opts->error on failure regardless of whether that field falls within the verified range - enabling a write beyond the checked region when opts__sz is deliberately undersized. No public exploit has been identified and EPSS probability is very low (0.20%, 10th percentile), but the CVSS 8.8 score with scope change reflects kernel memory corruption potential and privilege escalation risk for deployments where unprivileged BPF is enabled.

Technical ContextAI

The Linux kernel BPF subsystem exposes conntrack (netfilter connection tracking) lookup and allocation operations via kfuncs - privileged kernel functions callable from verified BPF programs. These kfuncs accept an opts struct pointer alongside an opts__sz size parameter; the BPF verifier uses opts__sz to bound the memory region it will validate. When the internal conntrack helper returns an error, the wrapper unconditionally writes an error code to opts->error. If a caller passes opts__sz smaller than the offset of the error field within the conntrack opts structure, that write lands at an address the verifier never checked - a classic out-of-bounds write (closest CWE analog is CWE-787, though NVD did not assign a CWE for this entry). The fix guards the opts->error write behind a size check, preserving correct behavior for the standard 12-byte and 16-byte opts layouts while rejecting invalid undersized sizes safely. Affected products are identified by CPE cpe:2.3:a:linux:linux:*:*:*:*:*:*:*:* across the vulnerable commit range starting at b4c2b9593a1c4c3a718370e34af28e817fd5e5c6.

RemediationAI

The primary remediation is to upgrade to a patched Linux kernel version - 7.1.5 (stable branch) or 7.2-rc1 - incorporating fix commits dd74c80203842a21b2ebb9f70d1260d9aa20fa05 and 6f6183a39533d727deaa5061cadae6dd9e6744d0 (see https://git.kernel.org/stable/c/dd74c80203842a21b2ebb9f70d1260d9aa20fa05). For systems where patching cannot be performed immediately, set sysctl kernel.unprivileged_bpf_disabled=1 to block standard users from loading any BPF programs - this eliminates the attack surface for non-privileged accounts entirely, though it will break eBPF-based observability tools (e.g., Cilium, Falco, bcc, bpftrace) running without explicit capabilities. On container platforms, restrict CAP_BPF and CAP_SYS_ADMIN from container runtimes via seccomp profiles or capability drop policies (e.g., Kubernetes securityContext.capabilities.drop). These workarounds do not protect against exploitation by processes that legitimately hold CAP_BPF, so patching remains the definitive fix.

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Vendor StatusVendor

SUSE

Severity: Moderate
Product Status
SUSE Linux Enterprise Desktop 15 SP7 Affected
SUSE Linux Enterprise Desktop 15 SP7 Affected
SUSE Linux Enterprise High Availability Extension 15 SP7 Affected
SUSE Linux Enterprise High Availability Extension 15 SP7 Affected
SUSE Linux Enterprise High Availability Extension 16.0 Affected

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EUVD-2026-59322 vulnerability details – vuln.today
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