Unrated

Arbitrary File Write via Symlink Validation Bypass in Language Servers for AWS

IdentifiersCVE-2026-12958CWE-59

CVE-2026-12958 is a high-severity local arbitrary file write vulnerability in Language Servers for AWS before version 1.69.0. The issue is caused by missing validation of symlinks when handling workspace content. If a user opens a maliciously crafted workspace containing a symlink that resolves to a path outside the workspace trust boundary, the language server may follow that symlink and write to an unintended file outside the workspace. The flaw breaks the intended workspace isolation model and is described in path traversal-related context, specifically through improper handling of symlink resolution.

For your environment

Are you exposed to this one?

Mallory correlates every CVE against your assets, your vendors, and active adversary campaigns. Know which vulnerabilities matter for you, not just which ones are loud.

Start free trial

ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation can allow modification of files outside the trusted workspace boundary. Depending on which target path is reachable and writable by the affected user, this can result in unauthorized alteration of local files, corruption of configuration or project data, and potentially follow-on compromise of the developer environment. The issue is local rather than remotely exploitable, but it can still have significant security impact when a victim opens an attacker-crafted workspace.

Mitigation

If you can’t patch tonight, do this now.

No workaround is available according to the advisory. Until patched, avoid opening untrusted workspaces and only trust workspaces from verified sources when prompted by the IDE. Restrict use of attacker-supplied project directories and review workspace contents for malicious symlinks before opening where feasible.

Remediation

Patch, then assume compromise.

Upgrade Language Servers for AWS to version 1.69.0 or later. AWS also advises upgrading affected bundled Amazon Q Developer IDE plugins to fixed releases or later, and ensuring any forked or derivative code incorporates the symlink-validation fix.

PUBLIC EXPLOITS

Exploits

No public exploits tracked yet. Mallory keeps watching.

VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType

Amazon Web ServicesLanguage Servers For Awsapplication

Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.

ACTIVITY FEED

Recent activity

8 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.

8 SOURCESView more in app

security weekNews

Jun 26, 2026

Amazon Q Flaw Enabled Cloud Credential Theft via Malicious Repositories - SecurityWeek

A related symbolic link handling issue in Amazon Q Developer/AWS Language Server mentioned alongside CVE-2026-12957.

the hacker newsNews

Jun 26, 2026

Amazon Q Developer Flaw Could Let Malicious Repos Run Code via MCP Configs

A flaw in Language Servers for AWS caused by a missing symlink check that could permit arbitrary file writes outside the workspace trust boundary.

cvefeed high severityNews

Jun 23, 2026

CVE-2026-12958 - Arbitrary file write in Language Servers for AWS

An arbitrary file write vulnerability in Language Servers for AWS caused by missing symlink validation, allowing writes outside the workspace trust boundary when a local user opens a maliciously crafted workspace.

What this page doesn’t show

The version that knows your environment.

This page is what’s public. Mallory adds the parts that aren’t: which of your assets are affected, which adversaries are exploiting it right now, which detections to deploy, and what to do tonight.

Start free trial

Exposure mapping

Query your assets running an affected version, and investigate the blast radius.

Threat actor evidence

Every observed campaign linking this CVE to a named adversary.

Associated malware

Malware families riding this exploit, with evidence and IOCs.

Detection signatures

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity4

Community discussion across Reddit, Mastodon, and other social sources.

EXTERNAL REFERENCES

MITRE CVE

cve.org · CVE-2026-12958

NVD

nvd.nist.gov/vuln/detail/CVE-2026-12958

MITRE CWE · CWE-59

cwe.mitre.org