CVE-2026-123783
What it is
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.
At a glance
- Exploitability
- Can be exploited over the network with a low-privilege account. High risk of data exposure, data tampering, service disruption.
- Fix
- A patch, advisory or fixed version is referenced. Upgrade or apply it.
Timeline
- PublishedDisclosed publicly on CVE.org and NVD
- Last updatedMost recent change to the record
Why it ranks here
- Exploited in the wild: no, CISA does not list it.
- Exploit odds: not scored yet.
- Severity: 8.7 HIGH (CVSS).
- Fix: a patch or advisory is linked.
Details
- Published
- Last modified
- Weakness
- CWE-184
- Record status
- Deferred
Attack profile CVSS 4.0 · 8.7
- Attack vector
- Network
- Complexity
- Low
- Attack requirements
- None
- Privileges needed
- Low
- User interaction
- None
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Raw vector
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
Is it in your code?
Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.
Read https://cve-list.com/agent/cve/CVE-2026-123783.md and follow it. Check whether this project is affected by CVE-2026-123783. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.
Fix and advisories
- https://github.com/Skyvern-AI/skyvern/commit/31a64c1a4b5dfaf1e76a7164845e10f2d68248dc
- https://github.com/Skyvern-AI/skyvern/pull/8937
References
- https://github.com/Skyvern-AI/skyvern
- https://github.com/Skyvern-AI/skyvern/blob/v1.0.56/skyvern/forge/sdk/workflow/code_block_safety.py#L106-L142
- https://github.com/Skyvern-AI/skyvern/blob/v1.0.56/skyvern/forge/sdk/workflow/service.py#L1509-L1511
- https://github.com/Skyvern-AI/skyvern/commit/31a64c1a4b5dfaf1e76a7164845e10f2d68248dc
- https://github.com/Skyvern-AI/skyvern/issues/8927
- https://github.com/Skyvern-AI/skyvern/pull/8937
- https://www.vulncheck.com/advisories/skyvern-through-1.0.56-script-sandbox-bypass-via-types-codetype-bytecode