CVE-2026-53765CWE-59

chrome-devtools-mcp: daemon.pid write follows symlinks in /tmp fallback runtime directory

Medium · published June 24, 2026

CVSS v3.1
6.1
EPSS
0%
Percentile
1.0
In the wild
Unconfirmed
What it is

Chrome DevTools for agents (chrome-devtools-mcp) lets your coding agent control and inspect a live Chrome browser. From 0.20.0 until 1.1.0, The chrome-devtools-mcp daemon writes its PID file with fs.writeFileSync() to a deterministic runtime path. On typical macOS environments, and on Linux sessions where $XDG_RUNTIME_DIR is unset, that runtime path falls back to /tmp/chrome-devtools-mcp-<uid>/daemon.pid. Because the write does not use O_NOFOLLOW, a local low-privilege user on the same POSIX host can pre-create /tmp/chrome-devtools-mcp-<victim_uid>/daemon.pid as a symlink to a file writable by the victim. When the victim later starts daemon mode, fs.writeFileSync() follows the symlink and truncates the target file to the daemon PID string. This vulnerability is fixed in 1.1.0.

The record
Technical detail
CVSS v3.1
6.1 · MEDIUM
Vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:L
CVSS v4.0
Not supplied
EPSS
0.00104 · 1.0th percentile
Weakness
CWE-59 · Improper Link Resolution Before File Access ('Link Following')
Published
2026-06-24T21:30Z
EPSS history
Timeline
  • 24 JUN 21:30Z
    chrome-devtools-mcp: daemon.pid write follows symlinks in /tmp fallback runtime directory
    cvelistv5