The check_alu_op() function in kernel/bpf/verifier.c in the Linux kernel through…
Priority LOW 25CWE-668Published · Updated
Key facts
- Attack vector
- Local
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Information disclosure
- Confidentiality · integrity · availability
- High · None · None
- Fix status
- Deferred Red Hat: fix deferred
Attack profile from CVSS 3.1 · NVD. Fix status from CNA and Red Hat. Impact type from CWE-668 and the CVSS impact.
Summary
The check_alu_op() function in kernel/bpf/verifier.c in the Linux kernel through v5.16-rc5 did not properly update bounds while handling the mov32 instruction, which allows local users to obtain potentially sensitive address information, aka a "pointer leak."
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00416 36th percentileScored 2026-11-08
Public exploit Yes 2 exploit referencesTagged by NVD
Fix Deferred Red Hat: fix deferred
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| — | — | all versions | — | No fix listed | CNA |
- — Vendor— Affected all versions Fixed in — No fix listed CNA
CPE configurations NVD · 6
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | before 5.16 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:5.16:rc1:*:*:*:*:*:* | 5.16 rc1 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:5.16:rc2:*:*:*:*:*:* | 5.16 rc2 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:5.16:rc3:*:*:*:*:*:* | 5.16 rc3 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:5.16:rc4:*:*:*:*:*:* | 5.16 rc4 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:5.16:rc5:*:*:*:*:*:* | 5.16 rc5 | Vulnerable | Linux |
- cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions before 5.16 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:5.16:rc1:*:*:*:*:*:* Versions 5.16 rc1 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:5.16:rc2:*:*:*:*:*:* Versions 5.16 rc2 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:5.16:rc3:*:*:*:*:*:* Versions 5.16 rc3 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:5.16:rc4:*:*:*:*:*:* Versions 5.16 rc4 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:5.16:rc5:*:*:*:*:*:* Versions 5.16 rc5 Vulnerable ·Linux
Remediation
No fixed version listed by the sources yet.
Vendor assessments
Red Hat
Red Hat rating: Low. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 8 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 9 | Affected | No fix yet: Fix deferred |
Not affected: 2 products
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
Timeline
- 2026-10-02 Threatist record created from CVE-2021-45402
- 2026-10-03 Alias added: GHSA-wj6w-52qh-v4q5
- 2026-10-08 CISA SSVC decision points changed
References
Exploit 2
More Linux Kernel vulnerabilities
- TI-2025-26358 tls: fix handling of zero-length records on the rx_list KEVCVSS 3.1CRITICAL 9.8
- TI-2026-38352 netfilter: bridge: make ebt_snat ARP rewrite writable KEVCVSS 3.1HIGH 8.8
- TI-2013-05264 The (1) get_user and (2) put_user API functions in the Linux kernel before 3.5.5 on the… KEVCVSS 3.1HIGH 8.8
- TI-2022-00125 Integer overflow in kernel KEVCVSS 3.1HIGH 8.4
- TI-2013-01864 The perf_swevent_init function in kernel/events/core.c in the Linux kernel before 3.8.9… KEVCVSS 3.1HIGH 8.4
- TI-2021-05514 Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACE KEVCVSS 3.1HIGH 8.3
Sources
- CVE-2021-45402 · CVE Program
- CVE-2021-45402 · NVD
- FIRST EPSS
- GHSA-wj6w-52qh-v4q5 · GitHub Advisory Database · CC BY 4.0
- CVE-2021-45402 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences