# CVE-2026-53400: i2c: core: fix adapter registration race

Status: published. Published: 2026-07-19. Updated: 2026-11-10.

In the Linux kernel, the following vulnerability has been resolved:

i2c: core: fix adapter registration race

Adapters can be looked up based on their id using i2c_get_adapter()
which takes a reference to the embedded struct device.

Make sure that the adapter (including its struct device) has been
initialised before adding it to the IDR to avoid accessing uninitialised
data which could, for example, lead to NULL-pointer dereferences or
use-after-free.

Note that the i2c-dev chardev, which is registered from a bus notifier,
currently uses i2c_get_adapter() so the adapter needs to be added to the
IDR before registration.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- Linux / Linux: ≥ 6e13e641841833cc2aa5baefe89bb04bc388801b; < 2e57c788e71f1763445f812eba4e0b4a2fbd0646 (affected, git); ≥ 6e13e641841833cc2aa5baefe89bb04bc388801b; < a4365bc41baaf67f3a5aa8556d23544e6ec7480a (affected, git); ≥ 6e13e641841833cc2aa5baefe89bb04bc388801b; < 1febb174815bcae56d73587e99e8f87e02f0784d (affected, git); ≥ 6e13e641841833cc2aa5baefe89bb04bc388801b; < da9d8d9711f78deebc202d0cffcf577e45ee8621 (affected, git); ≥ 6e13e641841833cc2aa5baefe89bb04bc388801b; < 78793c75dc6d0ff2e4d50ad617349b328a99054e (affected, git); ≥ 6e13e641841833cc2aa5baefe89bb04bc388801b; < 6a946038f2a5a8c29048c6af369d4e391448a5c5 (affected, git); ≥ 6e13e641841833cc2aa5baefe89bb04bc388801b; < a4c8094bbf4c6fa68b17e3b16f6a0a1b7a14f3e0 (affected, git); ≥ 6e13e641841833cc2aa5baefe89bb04bc388801b; < ba14d7cf2fe7284610a29854bdff22b2537d3ce6 (affected, git). Source: CNA: Linux
- Linux / Linux: 2.6.22 (affected); ≥ 0; < 2.6.22 (unaffected, semver); ≥ 5.10.261; ≤ 5.10.* (unaffected, semver); ≥ 5.15.212; ≤ 5.15.* (unaffected, semver); ≥ 6.1.178; ≤ 6.1.* (unaffected, semver); ≥ 6.6.145; ≤ 6.6.* (unaffected, semver); ≥ 6.12.95; ≤ 6.12.* (unaffected, semver); ≥ 6.18.38; ≤ 6.18.* (unaffected, semver); ≥ 7.1.3; ≤ 7.1.* (unaffected, semver); ≥ 7.2; ≤ * (unaffected, original_commit_for_fix). Source: CNA: Linux
- Siemens / SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0): ≥ V3.1.6; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0): ≥ V3.1.7; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0): ≥ V3.1.6; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0): ≥ V3.1.7; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0): ≥ V3.1.6; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0): ≥ V3.1.7; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AC0): ≥ V3.1.6; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AC0): ≥ V3.1.7; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIPLUS S7-1500 CPU 1518-4 PN/DP MFP (6AG1518-4AX00-4AC0): ≥ V3.1.6; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIPLUS S7-1500 CPU 1518-4 PN/DP MFP (6AG1518-4AX00-4AC0): ≥ V3.1.7; < * (affected, custom). Source: ADP: siemens-SADP

## Severity and prioritization

- CVSS 3.1: 7.8 (high); CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H; source: CNA: Linux

- CISA KEV: No listing in collected sources

- EPSS: 0.14% as of 2026-11-09; percentile 3.05%

- SSVC: exploitation none; automatable no; technical impact total; source ADP: CISA-ADP

- Weaknesses: CWE-362

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://git.kernel.org/stable/c/2e57c788e71f1763445f812eba4e0b4a2fbd0646 (CNA: Linux)

- https://git.kernel.org/stable/c/a4365bc41baaf67f3a5aa8556d23544e6ec7480a (CNA: Linux)

- https://git.kernel.org/stable/c/1febb174815bcae56d73587e99e8f87e02f0784d (CNA: Linux)

- https://git.kernel.org/stable/c/da9d8d9711f78deebc202d0cffcf577e45ee8621 (CNA: Linux)

- https://git.kernel.org/stable/c/78793c75dc6d0ff2e4d50ad617349b328a99054e (CNA: Linux)

- https://git.kernel.org/stable/c/6a946038f2a5a8c29048c6af369d4e391448a5c5 (CNA: Linux)

- https://git.kernel.org/stable/c/a4c8094bbf4c6fa68b17e3b16f6a0a1b7a14f3e0 (CNA: Linux)

- https://git.kernel.org/stable/c/ba14d7cf2fe7284610a29854bdff22b2537d3ce6 (CNA: Linux)

- https://cert-portal.siemens.com/productcert/html/ssa-019113.html (ADP: siemens-SADP)

- https://cert-portal.siemens.com/productcert/html/ssa-457936.html (ADP: siemens-SADP)

## Provenance

- CNA: Linux: https://www.cve.org/CVERecord?id=CVE-2026-53400; retrieved 2026-11-10; source updated 2026-11-10

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-53400; retrieved 2026-11-10; source updated Not reported

Revision: 3170f09dfa773061fdb12f069444d7d9331eb0ddaa5c08ea5015e84a0bd35e4f

Canonical: https://y2.dev/cve/CVE-2026-53400

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