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CVE-2026-123783: Skyvern Security Vulnerability

CVE-2026-123783 explained: high Security Vulnerability in Skyvern. CVSS 8.7. Affected versions, detection, fixes and CTEM priority.

Last updated: Nov 6, 2026

CVSS
8.7 HIGH
EPSS
n/a
CISA KEV
Not listed
CWE
CWE-184

Sources: National Vulnerability Database, CVE.org, CISA KEV, FIRST EPSS

CVE-2026-123783 Overview

Skyvern through 1.0.56 contains a sandbox bypass vulnerability that allows authenticated users to execute code by reconstructing functions from raw bytecode with types.CodeType. Attackers can deploy scripts that evade the is_safe_script_code AST denylist and import blocked modules such as subprocess or socket to run code in the Skyvern server process.

Critical Impact

Remote, authenticated attackers can exploit this Security Vulnerability in Skyvern. The CVSS base score is 8.7 (High).

Affected Products

  • Skyvern: see the vendor advisory for the exact affected versions

Discovery Timeline

  • 2026-11-06: CVE-2026-123783 published to the National Vulnerability Database by disclosure@vulncheck.com
  • 2026-11-06: last updated in the NVD database

Technical Details for CVE-2026-123783

Vulnerability Analysis

CVE-2026-123783 is a Security Vulnerability weakness (CWE-184) in Skyvern. Based on its CVSS vector, the flaw can be reached over the network, needs some level of access, and needs no user interaction.

With a CVSS base score of 8.7, apply the vendor fix and confirm exposure on internet facing and business critical assets first.

Root Cause

The vendor description states: Skyvern through 1.0.56 contains a sandbox bypass vulnerability that allows authenticated users to execute code by reconstructing functions from raw bytecode with types.CodeType. Attackers can deploy scripts that evade the is_safe_script_code AST denylist and import blocked modules such as subprocess or socket to run code in the Skyvern server process.

Attack Vector

Based on the CVSS vector, the flaw can be reached over the network, needs some level of access, and needs no user interaction. Attack complexity is low complexity.

No exploitation in the wild is confirmed by CISA at the time of the last update. Check the references below for any vendor or researcher proof of concept.

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/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

Detection Methods for CVE-2026-123783

Detection Strategies

  • Inventory every instance of Skyvern and compare the running version with the affected range above.
  • Check external attack surface scans for internet facing instances of the component.
  • Run an authenticated vulnerability scan once your scanner ships a check for this CVE.

Monitoring Recommendations

  • Forward Skyvern application, access and audit logs to your SIEM for retrospective hunting.
  • Alert on new processes, configuration changes or outbound connections from the affected service.
  • Track the vendor advisory and the CISA KEV catalog for changes in exploitation status.

How to Mitigate CVE-2026-123783

Immediate Actions Required

  • Apply the fixed version of Skyvern named in the vendor advisory.
  • Prioritize internet facing and business critical instances first.
  • Rescan after the change to confirm the exposure is closed.

Patch Information

Use the fixed version listed in the vendor advisory for Skyvern.

Workarounds

  • If patching must wait, restrict network access to the affected service and place it behind authentication or a web application firewall rule.

CWE References

Technical References

This entry is built directly from NVD, CISA KEV and EPSS data. Verify fixed versions in the vendor advisory before you deploy.

Frequently asked questions

CVE-2026-123783 is a high severity Security Vulnerability in Skyvern with a CVSS score of 8.7. Apply the vendor fix and confirm exposure on internet facing and business critical assets first.

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