Cyber Resilience

CVE-2026-22864

RCE in Deno ≤ 2.5.6

Public PoCRCECommand Injection
Published
15 January 2026
Modified
21 January 2026
Patch / advisory
View advisory
CVSS Score v3.1 8.1
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.0062 47th percentile
Risk Priority 60 floored blend · peak EPSS

Summary

CVE-2026-22864 is a high-severity Command Injection (CWE-77) vulnerability in Deno Deno. Its CVSS base score is 8.1 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Command and Scripting Interpreter (T1059); ranked at the 47th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SI-10 (Information Input Validation) — see the control section below for these in your framework.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

CVE-2026-22864 is a vulnerability in Deno, a JavaScript, TypeScript, and WebAssembly runtime, affecting versions prior to 2.5.6 on Windows systems. A previous patch intended to prevent spawning of batch or shell files by blocking paths with .bat or .cmd extensions used a case-sensitive comparison against lowercase literals, allowing bypass via alternate casing such as .BAT or .Bat. This issue, classified under CWE-77 (Command Injection), carries a CVSS v3.1 base score of 8.1 (AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H).

The vulnerability can be exploited by remote attackers requiring no privileges or user interaction, though it demands high attack complexity, likely due to crafting a suitable path with mixed-case extensions in Deno's process spawning APIs. Successful exploitation enables spawning arbitrary Windows batch or shell files, resulting in high-impact confidentiality, integrity, and availability violations, potentially leading to full system compromise within the Deno runtime environment.

Mitigation is provided in Deno version 2.5.6, which addresses the case-sensitivity flaw in the extension check. Official advisories recommend upgrading to this version, as detailed in the Deno release notes at https://github.com/denoland/deno/releases/tag/v2.5.6 and the security advisory at https://github.com/denoland/deno/security/advisories/GHSA-m3c4-prhw-mrx6.

OWASP Top 10 for Web (2025)

A05:2025 Injection

EU & UK References

Vulnerability Data

Deno is a JavaScript, TypeScript, and WebAssembly runtime. Before 2.5.6, a prior patch aimed to block spawning Windows batch/shell files by returning an error when a spawned path’s extension matched .bat or .cmd. That check performs a case-sensitive comparison against…

more

lowercase literals and therefore can be bypassed when the extension uses alternate casing (for example .BAT, .Bat, etc.). This vulnerability is fixed in 2.5.6.

CWE(s)
CWE-77

Related Threats

MITRE ATT&CK Enterprise Techniques

T1059 Command and Scripting Interpreter Execution
Adversaries may abuse command and script interpreters to execute commands, scripts, or binaries.
attack.mitre.org →
T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
attack.mitre.org →
T1059.001 PowerShell Execution
Adversaries may abuse PowerShell commands and scripts for execution.
attack.mitre.org →
T1059.003 Windows Command Shell Execution
Adversaries may abuse the Windows command shell for execution.
attack.mitre.org →
T1059.004 Unix Shell Execution
Adversaries may abuse Unix shell commands and scripts for execution.
attack.mitre.org →
T1059.008 Network Device CLI Execution
Adversaries may abuse scripting or built-in command line interpreters (CLI) on network devices to execute malicious command and payloads.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2024-32477Same product: Deno Deno
CVE-2026-27190Same product: Deno Deno
CVE-2026-32260Same product: Deno Deno
CVE-2024-27931Same product: Deno Deno
CVE-2024-27934Same product: Deno Deno
CVE-2024-27932Same product: Deno Deno
CVE-2025-61787Same product: Deno Deno
CVE-2025-48935Same product: Deno Deno
CVE-2024-27933Same product: Deno Deno
CVE-2025-48888Same product: Deno Deno

Affected Assets

deno
deno
≤ 2.5.6

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)

—

Validate
Prove the fix (OWASP ASVS)
  • V1.2.3
  • V1.2.5
  • V1.2.8
  • V1.2.9

Mitigating Controls (NIST 800-53 r5) AI

SA-11 Developer Testing and Evaluation good match

Developer testing and evaluation can discover command-construction flaws before deployment.

SI-10 Information Input Validation good match

Input validation directly stops construction of commands from untrusted data containing special elements.

SA-8 Security and Privacy Engineering Principles partial match

Secure engineering principles include proper neutralization and safe command construction practices.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure SDLC practices directly require input validation and neutralization that prevent command injection.

DE.CM-09 partial match
prevents

Runtime monitoring of software and data can detect anomalous command execution resulting from injection.

ID.RA-01 partial match
prevents

Identifying recorded vulnerabilities enables remediation of command-injection flaws before exploitation.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.8.28 Secure coding mostly match
prevents

Secure coding standards require proper escaping and parameterization of commands, directly eliminating CWE-77.

A.8.29 Security testing in development and acceptance mostly match
finds

Security testing in development catches command-injection vulnerabilities before release.

A.8.25 Secure development life cycle partial match
prevents

Secure development life cycle mandates input validation and command construction practices that directly prevent command injection.

A.8.26 Application security requirements partial match
prevents

Application security requirements explicitly call for controls against injection flaws including command injection.

A.8.27 Secure system architecture and engineering principles partial match
prevents

Secure architecture principles reduce the attack surface but do not prescribe the specific neutralization techniques needed.

A.8.31 Separation of development, test and production environments none match
none

Environment separation limits the blast radius of an exploited command injection but does not prevent the flaw itself.

References