What is CVE-2026-89066?

CVE-2026-89066 is OS command injection in the task synthesis component in projen. The supplied enrichment data classifies it as Remote Code Exec mapped to CWE-78 OS Command Injection; CWE-88 CWE-88.

Which versions are affected?

Affected product and version evidence is listed in the product table above. Current public advisories should be checked for exact version scope before patch targeting is finalized.

Is there active exploitation?

Active exploitation is not confirmed from current sources for CVE-2026-89066. If exploitation is not confirmed from current sources, teams should document that status and continue monitoring KEV, vendor, and telemetry updates.

No. CVE-2026-89066 is not listed in CISA KEV in the supplied enrichment data. KEV status should be monitored because it can change after initial disclosure or after exploitation becomes publicly confirmed.

Is there a public exploit?

A public PoC is not confirmed from current sources for CVE-2026-89066. Public exploit or PoC availability should raise triage priority, especially for exposed or business-critical systems.

How can defenders detect it?

Start with EDR process telemetry, host service logs where available. Look for vulnerability-class behavior, product errors, suspicious authentication events, exploit probes, and abnormal process activity based only on evidence that applies to the affected product.

How should teams prioritize it?

Prioritize CVE-2026-89066 using CVSS 7.8, EPSS 0%, KEV status, public PoC status, and asset exposure. Internet-facing, privileged, or business-critical deployments should be handled first.

Are workarounds available?

The supplied mitigation guidance says to apply vendor patches and restrict external exposure until fixed. Fixed-version evidence is listed in the mitigation section above.

Which threat actors are linked publicly?

No public threat actor linkage is confirmed from current sources. Do not attribute exploitation to a threat actor unless the source evidence explicitly supports that linkage.

What should be done in the next 24 hours?

Identify exposed assets running affected vendor/product/version combinations. Prioritize based on EPSS, PoC availability, and external exposure. Search available logs for exploit probes, errors, authentication anomalies, or suspicious child processes matching the vulnerability class. Open remediation tickets with affected assets, owners, evidence status, and detection coverage so decisions are traceable.

highRemote Code Exec

CVE-2026-89066

CVE-2026-89066 — OS command injection in the task synthesis component in projen

Improper neutralization of special elements used in an OS command in the task synthesis component in projen before 0.103.0 might allow context-dependent attackers to execute arbitrary commands on a developer workstation or continuous integration runner via shell metacharacters in project configuration values and repository file names that are interpolated into generated task definitions. To remediate this issue, users should upgrade to version 0.103.0 and then re-synthesize the project so that .projen/tasks.json is regenerated with the corrected task definitions. Upgrading alone is not sufficient because the generated task definition file is committed to the repository.

Published Sep 11, 2026Updated Sep 11, 2026Sources: NVD, AWS (CNA), GitHub, SOCRadar CTI

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the scoring sources call it.

Exploitation

Unreported

no source claims exploitation

EPSS

ahead of 0% of scored CVEs

Affects

AWS

projen

CVSS base

7.8

high · 2 sources

Remediation

The vendor's own words where we have them.

Upgrade projen to a fixed release. Apply vendor patches per advisory and restrict external exposure of the affected component until patched.

First 24 hours

Ordered from the record's own fields — exposure first, because you cannot patch what you have not found.

Identify exposed assets running affected vendor/product/version combinations.
Prioritize based on EPSS, PoC availability, and external exposure.
Search available logs for exploit probes, errors, authentication anomalies, or suspicious child processes matching the vulnerability class.

Affected scope

Vendor, product and version as the advisories word them.

Vendor	Product	Versions	Status
AWS	projen	0 to < 0.103.0	Vulnerable

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Availability

High

Confidentiality

High

Integrity

High

Scope

Unchanged

Attack Complexity

Low

Attack Vector

Local

Privileges Req

None

User Interaction

Required

Every base score collected

Sources score independently and disagree; each row says who scored it and under which version.

Score	Version	Severity	Expl.	Impact	Source
7.8	CVSS 3.1	high	1.8	5.9	CNA, AWS (CNA)
8.4	CVSS 4.0	high	—	—	AWS (CNA)

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Weakness & attack patterns

CWE-78OS Command Injection
CWE-88

Inferred from the weakness class — not observed against this CVE.

CAPEC-242 · Code InjectionCAPEC-35 · Leverage Executable Code in Non-Executable Files

Detection

Read off the CVSS vector and the weakness class. Starting points, not rules we have tested.

Search application, proxy, and WAF logs for requests touching /tasks.json.

EDR process telemetryhost service logs

Timeline

What happened to this CVE, newest first — with the readings a source repeats on a schedule counted underneath rather than listed.

2026
Added · CVSS 3.1 7.8 (AV:L)
Sep 11, 2026 · NVD
Initial · CVE published
Sep 11, 2026 · NVD

References

3 on the record

aws.amazon.com/security/security-bulletins/2026-108-aws/
Vendor Advisory
github.com/projen/projen/releases/tag/v0.103.0
Exploit, Third Party Advisory
github.com/projen/projen/security/advisories/GHSA-q6g4-h6vc-vqm8
Exploit, Third Party Advisory

Elsewhere on this site

AWSevery CVE for this vendor
Remote Code Execsame class
CWE-78other pages naming this weakness

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record1

What should defenders know first?

CVE-2026-89066 is OS command injection in the task synthesis component in projen, a high vulnerability affecting projen from AWS. The current evidence does not list it in CISA KEV, and the exploit status is: Active exploitation is not confirmed from current sources for CVE-2026-89066. Public exploit evidence is: A public PoC is not confirmed from current sources for CVE-2026-89066. The affected-version evidence is listed in the key facts and affected products tables. Defenders should first verify whether exposed or business-critical assets run those versions, then apply vendor patches or mitigations, restrict reachable attack surface, and preserve logs for detection review. CVSS 7.8 describes technical severity, while EPSS 0% helps estimate near-term exploit likelihood; neither replaces asset context. Unknown fields should remain explicit in tickets, and threat actor, IOC, victimology, or payload claims should not be added unless a cited source supports them. Monitor CISA KEV, vendor advisories, NVD changes, public PoC repositories, and internal telemetry for update triggers.