Security readout for executives and security teams
Plain-English summary
CVE-2026-22864 affects Deno on Windows before version 2.5.6. A previous protection intended to block risky Windows batch or command file execution checked file extensions case-sensitively, allowing differently cased extensions to bypass it. Organizations using Deno to run untrusted or externally influenced process-spawning logic should prioritize upgrading.
Executive priority
High priority for teams using Deno on Windows, especially in automation, build pipelines, developer tooling, or services processing untrusted input. Upgrade planning should be prompt because the flaw can undermine a prior command-injection defense.
Technical view
Deno before 2.5.6 has an incomplete Windows command-injection prevention fix. The runtime rejected spawned paths ending in lowercase .bat or .cmd, but the comparison was case-sensitive. Alternate extension casing could bypass the restriction. The issue is categorized as CWE-77 with CVSS 3.1 score 8.1 and is fixed in Deno 2.5.6.
Likely exposure
Exposure is most relevant where Deno runs on Windows and application code can spawn processes using paths influenced by users, files, packages, CI inputs, or external data. Non-Windows deployments are not described as affected in the provided sources.
Exploitation context
The CVE record rates attack complexity as high, with no privileges or user interaction required. The provided sources do not state active exploitation, and the CVE is not marked in KEV. Treat this as a serious platform-hardening issue rather than confirmed in-the-wild exploitation.
Researcher notes
This is a bypass of an earlier Windows-specific extension block for spawned batch or command files. The key root cause is case-sensitive comparison against lowercase extensions on a case-insensitive platform. Sources name the fixed version but provide limited operational detail beyond the advisory and release reference.
Mitigation direction
- Upgrade Deno to version 2.5.6 or later.
- Prioritize Windows hosts and CI runners using Deno.
- Review code paths that spawn external processes.
- Restrict untrusted input from influencing spawned executable paths.
- Monitor Deno security advisory and release notes for updates.
Validation and detection
- Inventory Deno versions across developer, server, and CI Windows systems.
- Confirm all affected installations are at 2.5.6 or later.
- Identify Deno applications using process-spawning APIs.
- Review whether spawned paths can be externally influenced.
- Document compensating controls where immediate upgrade is delayed.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-77: Command execution behavior lookup
Command injection weaknesses can lead defenders to review execution techniques and command interpreter telemetry. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2026-22864 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- High
- CVSS
- 8.1 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H2.25.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
8.1HighVector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/denoland/deno/security/advisories/GHSA-m3c4-prhw-mrx6CVE reference · x_refsource_CONFIRM
- https://github.com/denoland/deno/releases/tag/v2.5.6CVE reference · x_refsource_MISC
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.