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CVE-2026-43433 Linux CVE debrief

CVE-2026-43433 describes a Linux kernel rust_binder flaw where the kernel copied an offsets array into a target process’s VMA and then read the values back from that memory. The CVE text says this read-back was normally safe because the mapping is read-only, but it could become dangerous if another Binder bug somehow let the target process write to its own mapping. In that worst case, the kernel could misinterpret the sender’s intended offsets and enable privilege escalation. The fix removes the TOCTOU read path.

Vendor
Linux
Product
Unknown
CVSS
HIGH 7.8
CISA KEV
Not listed in stored evidence
Original CVE published
2026-05-08
Original CVE updated
2026-05-12
Advisory published
2026-05-08
Advisory updated
2026-05-12

Who should care

Linux kernel maintainers, distro security teams, and administrators running kernels with Binder/rust_binder support, especially on systems where untrusted local users can run code.

Technical summary

According to the CVE description, the Binder transaction path first copies an offsets array into the target process’s VMA and then reads the offsets back from that same mapping. That creates a time-of-check/time-of-use dependency on memory that is expected to stay read-only. If some other Binder issue allowed the target process to write to that mapping, the kernel could consume altered offsets and misinterpret the transaction. The referenced fix eliminates the read-back step so the kernel no longer trusts a value after writing it into the mapping.

Defensive priority

High

Recommended defensive actions

  • Apply kernel updates that include the referenced stable fixes for the rust_binder Binder path.
  • Verify whether your deployed kernel builds include the patches referenced by the official kernel.org stable links.
  • Prioritize rollout on systems that allow untrusted local users or multi-user workloads.
  • Track vendor and kernel advisories until NVD leaves the issue’s 'Undergoing Analysis' state.
  • Review whether Binder/rust_binder is enabled in your deployment and include it in kernel patch validation.

Evidence notes

The CVE record was published on 2026-05-08 and modified on 2026-05-12. NVD lists the issue as 'Undergoing Analysis' and provides CVSS 3.1 vector AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. The supplied CVE description explicitly says the issue is not expected to be exploitable without another Binder bug. The source corpus includes three official kernel.org stable references, which appear to be the fix backports.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-43433 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-43433

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-43433 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-43433

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/3672141c93b7a0c0132bf5d5021a4b7f1d663aaa

    416baaa9-dc9f-4396-8d5f-8c081fb06d67

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/4cb9e13fec0de7c942f5f927469beb8e48ddd20f

    416baaa9-dc9f-4396-8d5f-8c081fb06d67

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/e19afb53f7723b3bd22224f2b0c7dcfa70bb973f

    416baaa9-dc9f-4396-8d5f-8c081fb06d67

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.