Security Digest · Vulnerability record
CVE-2026-73414: Shescape: Shell injection via unescaped parentheses on Windows with CMD
Shescape is a simple shell escape library for JavaScript.
CVSS 9.2 Critical EPSS 0.9% · p59
Should you act?
Critical and remotely reachable
No known exploitation yet, but it is network-reachable without credentials. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.
- No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
- EPSS 0.9%, percentile 59: FIRST’s model estimates a 0.9% chance of exploitation activity in the next 30 days, higher than 59% of all scored CVEs (moderate). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Only applies if your dependency tree includes
shescape(npm) < 2.1.14, fixed in 2.1.14;shescape(npm) >= 3.0.0, < 3.0.1, fixed in 3.0.1. Check your lockfile, including transitive dependencies.
What it is
Shescape is a simple shell escape library for JavaScript. Prior to 2.1.14 and 3.0.1, getEscapeFunction in src/internal/win/cmd.js does not escape ( and ) when applications use the escape or escapeAll APIs on Windows with shell set to cmd.exe, or with shell set to true when CMD is the default. An attacker-controlled argument can break out of a parenthesized CMD construct and inject shell syntax depending on the original command, resulting in arbitrary command execution. This issue is fixed in versions 2.1.14 and 3.0.1.
From the GitHub advisory
Impact
This impacts users of Shescape on Windows that explicitly configure shell to CMD, or true with the default shell being CMD, using the escape and escapeAll APIs.
An attacker may be able to achieve shell injection depending on the original command.
Patches
This bug has been patched in [v2.1.14] and [v3.0.1] which you can upgrade to now.
Weakness type: CWE-78, CWE-150.
Product: shescape (npm) · Assigned by: GitHub_M · Published: 2026-08-12
Affected and fixed versions
| Ecosystem | Package | Vulnerable | First fixed |
|---|---|---|---|
| npm | shescape | < 2.1.14 | 2.1.14 |
| npm | shescape | >= 3.0.0, < 3.0.1 | 3.0.1 |
| Vendor | Product | Affected versions (per CVE record) |
|---|---|---|
| ericcornelissen | shescape | < 2.1.14, >= 3.0.0, < 3.0.1 |
Severity scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_M | 4.0 | 9.2 Critical | CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N |
| GitHub | 4.0 | 9.2 | CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N |
- Attack vector: network (remotely reachable)
- Attack complexity: low
- Attack requirements: present (depends on deployment conditions)
- Privileges required: none (no login)
- User interaction: none
CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.
Exploitation and urgency
- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation none, automatable yes, technical impact total.
- FIRST EPSS (model of 2026-10-21): 0.89% probability of exploitation activity in the next 30 days; percentile 59.
Timeline
- — GitHub-reviewed advisory GHSA-w4hw-qcx7-56pr published (critical)
- — CVE record published by GitHub_M
- — CVE record last updated
Sources and references
Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.
Vulnerability records
- GitHub Advisory GHSA-w4hw-qcx7-56pr github.com
- CVE.org record CVE-2026-73414 cve.org
- NVD entry CVE-2026-73414 nvd.nist.gov
Other references from the CVE record and advisory
- github.com github.com
- github.com github.com
- github.com github.com
- github.com github.com
- github.com github.com
- github.com github.com
- github.com github.com
- github.com github.com