Security readout for executives and security teams
Plain-English summary
GitHub Copilot Plugin for JetBrains IDEs version 1.0.0 contains a command-injection flaw. An unauthenticated network attacker could potentially execute code after required user interaction, risking developer credentials, source code, and workstation availability. The supplied evidence does not identify other affected versions or describe the required interaction.
Executive priority
Treat this as a high-priority developer-endpoint issue. Remediate affected installations promptly because successful exploitation could compromise source code, credentials, and software-delivery systems. Escalate systems with privileged development or production access, while avoiding claims of an active campaign unsupported by current evidence.
Technical view
CVE-2026-21516 is CWE-77 command injection with CVSS 3.1 score 8.8. The vector indicates network access, low attack complexity, no privileges, required user interaction, unchanged scope, and high confidentiality, integrity, and availability impact. The source bundle identifies only plugin version 1.0.0 as affected.
Likely exposure
Exposure is indicated where GitHub Copilot Plugin for JetBrains IDEs version 1.0.0 is installed. Prioritize developer workstations with access to source repositories, credentials, signing material, deployment systems, or production administration. The bundle does not establish whether earlier or later versions are affected.
Exploitation context
The vulnerability permits unauthorized command injection over a network but requires user interaction. CISA KEV status is false, and the supplied sources provide no evidence of active exploitation or public exploit availability. The precise delivery method, triggering action, and prerequisites are not included.
Researcher notes
The record establishes CWE-77, remote reachability, required user interaction, and affected version 1.0.0. It does not provide the vulnerable command path, interaction mechanism, fixed version, indicators of compromise, or exploitation evidence. Use the Microsoft advisory for remediation specifics and avoid extrapolating the affected-version range.
Mitigation direction
- Inventory JetBrains installations and identify GitHub Copilot plugin version 1.0.0.
- Review the Microsoft advisory and apply its official update or remediation guidance.
- Prioritize systems holding repository, cloud, deployment, or signing credentials.
- Restrict or disable the affected plugin if vendor remediation cannot be applied promptly.
- Rotate sensitive credentials if investigation finds credible evidence of compromise.
Validation and detection
- Confirm the installed plugin version on every managed JetBrains workstation.
- Verify the affected version is removed or updated according to Microsoft guidance.
- Review endpoint telemetry for unexpected child processes or commands originating from JetBrains.
- Check repository, identity, and deployment logs for unusual activity around affected workstations.
- Document systems not remediated and apply compensating controls pending vendor guidance.
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 lookupExecution behavior lookup
The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2026-21516 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
- 8.8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
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.
SSVC decision data
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:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C2.85.9microsoftVulnerability scoring details
Base CVSS 3.1 score
8.8HighVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- CVE publishedCVE Program
The CVE record was published.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
Source materials
- CVE List V5 sourceCVE List V5
- GitHub Copilot for Jetbrains Remote Code Execution VulnerabilityCVE reference, microsoft · vendor-advisory, patch
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.
Improper Neutralization of Special Elements used in a Command ('Command Injection')
Improper Neutralization of Special Elements used in a Command ('Command Injection') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.