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TI-2026-85963 Aliases CVE-2026-123783GHSA-2555-vffj-g73c

Sandbox bypass in Skyvern script execution lets users run code on server

Priority LOW 38CWE-184Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
—
Confidentiality · integrity · availability
High · High · High
Fix status
No fix listed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA.

Summary

Skyvern through 1.0.56 contains a sandbox bypass that lets an authenticated user run code on the server. The script checker, an incomplete denylist (CWE-184), can be evaded by rebuilding functions from raw bytecode with types.CodeType. An authenticated remote attacker with low privileges can deploy scripts that import blocked modules such as subprocess or socket and run code in the Skyvern server process.

Written with Claude Haiku 5.5 from the sources below · 2026-11-06

Description from the CNA

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.

Why it matters now

EPSS 0.00557 46th percentileScored 2026-11-07
Fix No fix listed No fixed version in the sources yet

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

VendorProductAffected versionsFixed inStatusSource
Skyvern-AIskyvernup to 1.0.56—No fix listedCNA
  • skyvern VendorSkyvern-AI Affected up to 1.0.56 Fixed in — No fix listed CNA

Remediation

The sources list no fixed version for skyvern.

Written with Claude Haiku 5.5 from the sources below · 2026-11-06

Timeline

  1. 2026-11-06 Threatist record created from CVE-2026-123783
  2. 2026-11-06 Alias added: GHSA-2555-vffj-g73c
  3. 2026-11-08 Priority changed: MEDIUM → LOW

References

Patch 2

Other 4

  • TI-2026-56844 Skyvern before 1.0.45 Sandbox Escape via TextPromptBlock CVSS 4.0HIGH 8.7

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences