# CVE-2026-64375: proc: protect ptrace_may_access() with exec_update_lock (FD links)

Status: published. Published: 2026-07-25. Updated: 2026-11-10.

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

proc: protect ptrace_may_access() with exec_update_lock (FD links)

proc_pid_get_link() and proc_pid_readlink() currently look up the task from
the pid once, then do the ptrace access check on that task, then look up
the task from the pid a second time to do the actual access.
That's racy in several ways.

To fix it, pass the task to the ->proc_get_link() handler, and instead of
proc_fd_access_allowed(), introduce a new helper call_proc_get_link() that
looks up and locks the task, does the access check, and calls
->proc_get_link().

## Remediation

No remediation reported in collected sources

## Affected products and versions

- Linux / Linux: ≥ 778c1144771f0064b6f51bee865cceb0d996f2f9; < 6253dfee5afba536bb54fc6fe6c091c3758fafe1 (affected, git); ≥ 778c1144771f0064b6f51bee865cceb0d996f2f9; < 65bf0d2b6e914f1448d6a2fde193dcf60936a651 (affected, git); ≥ 778c1144771f0064b6f51bee865cceb0d996f2f9; < de497d7aa2fae453a7e7c8f7d3e8682e565e3aaf (affected, git); ≥ 778c1144771f0064b6f51bee865cceb0d996f2f9; < 138c692d2b2d63d26f2eb957d0e4fcc5d61f9ff2 (affected, git); ≥ 778c1144771f0064b6f51bee865cceb0d996f2f9; < 83b17872e3166c295c599279fc9562ac3840c638 (affected, git); ≥ 778c1144771f0064b6f51bee865cceb0d996f2f9; < 497c6bae5167428596575f20af6613ff5671f383 (affected, git); ≥ 778c1144771f0064b6f51bee865cceb0d996f2f9; < dfd1894cb64cbd8758b461ed713800fe73db4f82 (affected, git); ≥ 778c1144771f0064b6f51bee865cceb0d996f2f9; < 6255da28d4bb5349fe18e84cb043ccd394eba75d (affected, git). Source: CNA: Linux
- Linux / Linux: 2.6.18 (affected); ≥ 0; < 2.6.18 (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); ≥ 6.12.97; ≤ 6.12.* (unaffected, semver); ≥ 6.18.40; ≤ 6.18.* (unaffected, semver); ≥ 7.1.4; ≤ 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: 0.10% as of 2026-11-09; percentile 1.06%

- 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/6253dfee5afba536bb54fc6fe6c091c3758fafe1 (CNA: Linux)

- https://git.kernel.org/stable/c/65bf0d2b6e914f1448d6a2fde193dcf60936a651 (CNA: Linux)

- https://git.kernel.org/stable/c/de497d7aa2fae453a7e7c8f7d3e8682e565e3aaf (CNA: Linux)

- https://git.kernel.org/stable/c/138c692d2b2d63d26f2eb957d0e4fcc5d61f9ff2 (CNA: Linux)

- https://git.kernel.org/stable/c/83b17872e3166c295c599279fc9562ac3840c638 (CNA: Linux)

- https://git.kernel.org/stable/c/497c6bae5167428596575f20af6613ff5671f383 (CNA: Linux)

- https://git.kernel.org/stable/c/dfd1894cb64cbd8758b461ed713800fe73db4f82 (CNA: Linux)

- https://git.kernel.org/stable/c/6255da28d4bb5349fe18e84cb043ccd394eba75d (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-2026-64375; retrieved 2026-11-10; source updated 2026-11-10

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-64375; retrieved 2026-11-10; source updated Not reported

Revision: e481a83d1ac6656b41b739d281b37232b40dd616176f8186f085c5160024552a

Canonical: https://y2.dev/cve/CVE-2026-64375

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