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AWS Toolkit CVE-2026-107332

| EUVDEUVD-2026-95128 MEDIUM
Incorrect Default Permissions (CWE-276)
2026-10-08 AMZN
6.8
CVSS 4.0 · Vendor: AMZN
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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

  1. Access
    Obtain local account on shared host
  2. Exploit
    Locate world-readable token cache file
  3. Execution
    Read CodeCatalyst bearer token
  4. Impact
    Replay token to impersonate victim

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A01:2025 - Broken Access Control
ASVS 5.0
V13 - Configuration Default permission hardening
MITRE ATT&CK

1 technique across 1 tactic: Privilege Escalation

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

Exploitation Conditions

Requires (1) a local account on the same host and (2) a victim who has authenticated the AWS Toolkit for VS Code's CodeCatalyst connection, producing a token cache file written with world-readable permissions by versions before 4.10.0. Exploitation is LIMITED to systems where multiple users share access - on a single-user developer workstation no second principal exists to abuse the permissions. No remote vector, no user interaction, and no elevated privileges are needed beyond an ordinary local login; the stolen token's usefulness is further bounded by its validity lifetime and the victim's CodeCatalyst permissions.

Impact

This is a genuine but lower-tier priority - a local information-disclosure flaw, not a remote-exploitable critical. The CVSS 4.0 vector (AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N) is internally consistent with the description: exploitation requires an existing local account (PR:L) on a machine where a victim has authenticated the AWS Toolkit, and the only impact is confidentiality (VC:H) - the theft of CodeCatalyst bearer tokens - with no integrity or availability impact. The 6.8 'medium' score accurately reflects that the attacker must already have a foothold on the host. No EPSS score, CISA KEV entry, SSVC decision, or public POC was supplied in the input, which is unsurprising for a local file-permission issue reported by the vendor (AMZN) rather than observed in the wild. There is no conflict between the CVSS vector and the description - both point to local access. The practical risk is confined to multi-user hosts, shared/CI build machines, or any system an attacker can access locally; on a single-user developer workstation the exposure is minimal. Downstream impact can be meaningful: a stolen bearer token grants access to the victim's CodeCatalyst resources (source code, dev environments), so treat it as higher priority on shared infrastructure.

Exploit ScenarioDerived

On a shared or multi-user host (e.g., a build server or jump box) where a developer has signed into the AWS Toolkit for VS Code, a second local user with an unprivileged account reads the world-readable token cache file and extracts the victim's CodeCatalyst bearer token. The attacker then replays that token to access the victim's CodeCatalyst projects and dev environments. No public exploit is required - the attack is a simple file read; no POC was identified in the input.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).
Patch available 0.1% exploitation probability (EPSS)

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AnalysisAIv1 – Oct 08, 2026

World-readable CodeCatalyst token cache files in AWS Toolkit for VS Code versions before 4.10.0 let any other local user on the same host recover bearer tokens for a victim who has connected the CodeCatalyst integration. The flaw is a local information-disclosure and privilege-escalation concern (CWE-276, CVSS 6.8) rather than a remote attack: it requires a shared multi-user system, an ordinary local login, no user interaction, and no elevated privileges, and yields only read impact (confidentiality) with no integrity or availability loss. No public exploit code has been identified at time of analysis and the issue is not reported as actively exploited; the vendor has released a fix in version 4.10.0.

RemediationAI

Upgrade the AWS Toolkit for VS Code extension to version 4.10.0 or later (vendor-released patch: 4.10.0), available at https://github.com/aws/aws-toolkit-vscode/releases/tag/toolkit/v4.10.0 and described in the AWS security bulletin at https://aws.amazon.com/security/security-bulletins/2026-129-aws/. If immediate upgrade is not possible, restrict access to the extension's token cache: locate the on-disk token cache file and tighten its permissions to owner-only (for example chmod 600 on POSIX systems), accepting the trade-off that the extension may rewrite the file with permissive mode bits on the next token refresh, so the change must be re-applied until patched. Additional compensating controls on shared or multi-user hosts include removing or rotating cached CodeCatalyst tokens after the fix is applied (revoke the exposed token in CodeCatalyst so a previously read copy cannot be reused), clearing cached credentials before handing the machine to another user, and restricting who may log in interactively to developer workstations that hold CodeCatalyst credentials. The only fully reliable mitigation is the 4.10.0 upgrade, since the root cause is the default file mode chosen by the extension rather than an operator misconfiguration.

Affected VersionsENISA

aws-toolkit-vscode 0 <4.10.0

Affected Packages

euvd aws_toolkit_vscode fix: 4.10.0

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in euvd

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

The issue is CWE-276 (Incorrect Default Permissions) in the CodeCatalyst connection handler of the AWS Toolkit for VS Code extension. When a developer authenticates the CodeCatalyst integration, the extension persists the resulting bearer token to an on-disk token cache; before version 4.10.0 those cache files were created with overly permissive mode bits that left them readable by other principals on the host. Because the artifact is a bearer credential, anyone able to read the file can reuse it against CodeCatalyst within the token's remaining validity lifetime, subject to the victim's own CodeCatalyst permissions. The affected CPE entry is cpe:2.3:a:aws:aws-toolkit-vscode:*:*:*:*:*:*:*:*, matching the extension across all platforms it ships on (VS Code runs on the developer's workstation, so the exposure surface is the local filesystem rather than a network service). The assessed vector CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N confirms a local, low-complexity, low-privilege, no-interaction path with high confidentiality impact and no integrity or availability effect. Attack complexity is low and no race or special timing is required; the only structural prerequisite is the presence of a second local principal who can traverse the directory and open the cache file.

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Severity by source

Vendor (AMZN) PRIMARY 6.8 MEDIUM
CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
vuln.today AI 5.5 MEDIUM

Local read of a world-readable cache by any logged-in user gives AV:L/AC:L/PR:L/UI:N; impact is token disclosure only, so C:H, I:N, A:N, scope unchanged.

3.1 AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
4.0 AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N

Primary rating from Vendor (AMZN).

CVSS VectorVendor: AMZN

Attack Vector
Local
Attack Complexity
Low
Attack Requirements
None
Privileges Required
Low
User Interaction
None
Vulnerable system: Confidentiality
High
Vulnerable system: Integrity
None
Vulnerable system: Availability
None
Subsequent system: Confidentiality
None
Subsequent system: Integrity
None
Subsequent system: Availability
None

DescriptionCVE.org

Insecure file permissions in the CodeCatalyst connection handler in AWS Toolkit for VS Code before 4.10.0 allowed local users to obtain CodeCatalyst bearer tokens via reading world-readable token cache files.

To mitigate this issue, users should upgrade to version 4.10.0 or later.

Threat Intelligence Overview

EPSS Score
0.1%
Top 99% exploitable
Prevalence
Medium
popular VS Code extension among AWS developers, not universally deployed
Data Quality
6 sources
Confidence: High

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity MEDIUM
CISA KEV No
Public POC No
EPSS 0.1%
Patch available Yes
Active threat No
Deciding rule
MEDIUM severity (CVSS 4.0-6.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Defer
Exploitation
None
System Exposure· derived
Small
Automatable
No
Human Impact· derived
Medium
Technical Impact
Partial

Priority Score

34
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +34
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Privilege escalation occurs when an attacker leverages flaws in access control mechanisms to gain permissions beyond what they were originally granted.

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