UBUNTU-CVE-2026-43333
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.
02 / AFFECTED SOFTWARE
Affected packages
59 explicit affected versions
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45 explicit affected versions
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78 explicit affected versions
14 explicit affected versions
11 explicit affected versions
39 explicit affected versions
77 explicit affected versions
03 / CONNECTIONS
Connected vulnerabilities
04 / EVIDENCE
Source records
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.
05 / REFERENCES
Further evidence
- https://git.kernel.org/linus/b0db1accbc7395657c2b79db59fa9fae0d6656f3
- https://git.kernel.org/stable/c/10bc4a4dcded509c5d5c67d497900c3922c604cd
- https://git.kernel.org/stable/c/21a10c06ffae24cb01fd174a7ab7736001d2ea56
- https://git.kernel.org/stable/c/4f6c99dc0420f1a3d671c1b8ab8a7ac84d9cba09
- https://git.kernel.org/stable/c/63276547debc4d8a73eefb2c5273b2a905c961b0
- https://git.kernel.org/stable/c/70abd9d118da2f56beb4ec22e3a29becae373535
- https://git.kernel.org/stable/c/8755066f7bd0f4ac46a29d1708c7b20894539252
- https://git.kernel.org/stable/c/b0db1accbc7395657c2b79db59fa9fae0d6656f3
- https://ubuntu.com/security/CVE-2026-43333
- https://ubuntu.com/security/notices/USN-8567-1
- https://ubuntu.com/security/notices/USN-8574-1
- https://ubuntu.com/security/notices/USN-8574-2
- https://ubuntu.com/security/notices/USN-8574-3
- https://ubuntu.com/security/notices/USN-8575-1
- https://ubuntu.com/security/notices/USN-8575-2
- https://ubuntu.com/security/notices/USN-8575-3
- https://ubuntu.com/security/notices/USN-8576-1
- https://ubuntu.com/security/notices/USN-8576-2
- https://ubuntu.com/security/notices/USN-8595-1
- https://ubuntu.com/security/notices/USN-8595-2
- https://ubuntu.com/security/notices/USN-8595-3
- https://ubuntu.com/security/notices/USN-8596-1
- https://ubuntu.com/security/notices/USN-8597-1
- https://ubuntu.com/security/notices/USN-8606-1
- https://ubuntu.com/security/notices/USN-8607-1
- https://ubuntu.com/security/notices/USN-8608-1
- https://ubuntu.com/security/notices/USN-8609-1
- https://ubuntu.com/security/notices/USN-8610-1
- https://ubuntu.com/security/notices/USN-8619-1
- https://ubuntu.com/security/notices/USN-8620-1
- https://ubuntu.com/security/notices/USN-8620-2
- https://ubuntu.com/security/notices/USN-8620-3
- https://ubuntu.com/security/notices/USN-8620-4
- https://www.cve.org/CVERecord?id=CVE-2026-43333