VulnerabilityPublished 8 May 2026Updated 6 Nov 2026

CVE-2026-43333: Linux kernel · bpf: reject direct access to nullable PTR_TO_BUF pointers

Affects Linux kernelSource CVE Database V5

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Not known to be exploited · fixed in b0db1accbc7395657c2b79db59fa9fae0d6656f3 : update Linux kernel when convenient.

Data as of 6 Nov 2026, 15:49 UTC

Severity

Unrated

Rated by Threat Radar · No CVSS score from NVD or the CNA

Thin evidence

One scorer or none

Exploitation: No evidence of active exploitation and no public proof of concept
Automatable: Attackers cannot reliably automate steps 1–4 of the kill chain
Technical impact: Limited control over the software or limited information exposure

CISA SSVC assessment, 2026-11-06.

Patch

Available – fixed in b0db1accbc7395657c2b79db59fa9fae0d6656f3, 63276547debc4d8a73eefb2c5273b2a905c961b0, 8755066f7bd0f4ac46a29d1708c7b20894539252 +6

Exploitation evidence

Disclosed: evidence found.
CVE published 8 May 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 6 Nov 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected >=5.15.37 <5.15.203 >=5.16.11 <5.17	Fixed in b0db1accbc7395657c2b79db59fa9fae0d6656f3 63276547debc4d8a73eefb2c5273b2a905c961b0 8755066f7bd0f4ac46a29d1708c7b20894539252 70abd9d118da2f56beb4ec22e3a29becae373535 21a10c06ffae24cb01fd174a7ab7736001d2ea56 10bc4a4dcded509c5d5c67d497900c3922c604cd 5.17 5.15.203 4f6c99dc0420f1a3d671c1b8ab8a7ac84d9cba09
LinuxLinux	Affected =5.17	Fixed in–

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.

References

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