CVE & CISA-KEV Catalog

CVE-2026-43333

MEDIUM
5.5
CVSS v3
NVD

Description

In the Linux kernel, the following vulnerability has been resolved: bpf: reject direct access to nullable PTR_TO_BUF pointers check_mem_access() matches PTR_TO_BUF via base_type() which strips PTR_MAYBE_NULL, allowing direct dereference without a null check. Map iterator ctx->key and ctx->value are PTR_TO_BUF | PTR_MAYBE_NULL. On stop callbacks these are NULL, causing a kernel NULL dereference. Add a type_may_be_null() guard to the PTR_TO_BUF branch, matching the existing PTR_TO_BTF_ID pattern.

How to fix

Remediation Available
linuxDebian
Fixed in:6.1.170-1CVE-2026-43333
Fixed in:6.12.85-1CVE-2026-43333
Fixed in:6.19.12-1CVE-2026-43333

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorLocal
Attack ComplexityLow
Privileges RequiredLow
User InteractionNone
ScopeUnchanged

Impact

ConfidentialityNone
IntegrityNone
AvailabilityHigh

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Exploit Intelligence

0.12%probability of exploitation in 30 days
2ndpercentile

Low risk: more likely to be exploited than 2% of all known CVEs.

References

Related Vulnerabilities

Other CWE-476 (NULL Pointer Dereference) vulnerabilities, ordered by exploit likelihood. View all

CVESeverityCVSSEPSSExploitedFix
CVE-2023-21758High7.592%-Fix
CVE-2023-21547High7.588%-Fix
CVE-2014-3470Medium4.386%-Fix
CVE-2021-44224High8.282%-Fix
CVE-2016-0742High7.582%-Fix
CVE-2009-1386Medium5.080%-Fix
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-05-15.