Which versions of Language Servers for AWS are affected by CVE-2026-12958?

AWS Language Servers in versions prior to 1.69.0 contain a vulnerability that allows attackers to write malicious files to systems when developers open untrusted workspaces, potentially compromising…. A patch is available.

How to fix or mitigate CVE-2026-12958?

Within 24 hours: Conduct inventory of AWS Language Server deployments; document all versions currently in use and affected systems. Within 7 days: Restrict language server usage to trusted, locally-maintained workspaces; implement mandatory code review for workspace configurations and external workspace sources; consider disabling language server features in non-critical development environments. Within 30 days: Monitor vendor advisories for security patch releases; prepare patching plan and test in staging environment; establish ongoing workspace security governance and validation processes.

Language Servers for AWS CVE-2026-12958

Q: What is the CVSS score of CVE-2026-12958?

CVE-2026-12958 has a CVSS 4.0 base score of 8.5 (High). CVSS vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X. EPSS exploitation probability: 0.1%.

EUVD-2026-38489 HIGH

UNIX Symbolic Link (Symlink) Following (CWE-61)

2026-06-23 AMZN

Information Disclosure Language Servers For Aws

8.5

CVSS 4.0 · Vendor: AMZN

Severity by source

Vendor (AMZN) PRIMARY

8.5 HIGH

CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

vuln.today AI

7.8 HIGH

Local vector via opened workspace, no prior privileges needed but victim must open the project (UI:R); arbitrary file write yields high C/I/A on user files.

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

4.0 AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Primary rating from Vendor (AMZN).

CVSS VectorVendor: AMZN

Attack Vector

Local

Attack Complexity

Low

Privileges Required

None

User Interaction

Scope

Lifecycle Timeline

Patch available

Jun 23, 2026 - 18:17 EUVD

Analysis Generated

Jun 23, 2026 - 17:00 vuln.today

DescriptionCVE.org

Missing symlink validation in Language Servers for AWS may allow an arbitrary file write outside of the workspace trust boundary. This may occur when a local user opens a workspace with a maliciously crafted symlink that resolves to a file path outside the workspace trust boundary.

To remediate this issue, users should upgrade to version 1.69.0 or higher.

AnalysisAI

Arbitrary file write in AWS Language Servers (versions prior to 1.69.0) allows a local attacker to escape the workspace trust boundary by tricking a user into opening a workspace containing a maliciously crafted symbolic link. Because the language server fails to validate symlink targets, files written through normal language-server operations can land at arbitrary paths on disk, enabling tampering with sensitive files outside the workspace. No public exploit identified at time of analysis, and the issue is not listed in CISA KEV.

Technical ContextAI

AWS Language Servers implement the Language Server Protocol (LSP) backend that powers AWS developer tooling such as the AWS Toolkit and Q-style coding assistants in IDEs (cpe:2.3:a:amazon_web_services:language_servers_for_aws). The flaw is a classic CWE-61 (UNIX Symbolic Link Following) weakness: when the server resolves or writes paths inside a user-opened workspace, it does not canonicalize symlink targets against the workspace root, so a symlink inside the workspace pointing to an absolute path elsewhere on disk is silently followed. Workspace trust is a common IDE security boundary intended to sandbox untrusted projects, and this defect punches a hole through that boundary at the file I/O layer.

RemediationAI

Vendor-released patch: upgrade Language Servers for AWS to version 1.69.0 or later as directed by AWS security bulletin 2026-047 (https://aws.amazon.com/security/security-bulletins/2026-047-aws/), and update any IDE extensions or toolkits that embed the language server so the bundled version is also at 1.69.0+. Until patched, developers should avoid opening untrusted or unreviewed workspaces with AWS language features enabled, disable the AWS language server extension when reviewing third-party repositories, and on Unix systems consider mounting clone directories with the nosymfollow option or auditing repositories for unexpected symlinks before opening - these workarounds reduce risk but break legitimate symlink-based project layouts.