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workerd

By Cloudflare Bug bounty on Sorona cloudflare.com

Accepting reports open-source
Top reward
$3,750
Top severity paid
High
Assets in scope
11
Public CVEs
60
Last change
No changes yet

At a glance

What to know before you start testing.

Pays up to $3,750
for high bugs, from $625.
Partial safe harbor
Some legal protection; read the terms.
Replies within 10 days
As the policy promises.
Publish after a fix
Coordinate the timing with the company.

Rewards

What Sorona lists as the payout for each severity.

Severity Reward
High $3,750
Medium $938
Low $625
Response
Within 10 days 10 business days First response
Safe harbor
Partial Sorona will not pursue legal action against you for good-faith research submitted to us in line with this policy. We cannot speak for the upstream project, its vendor, or any third party, and we do not grant authorization on their behalf.

Summarised with AI from the program policy on Sorona, read 12 Nov 2026, and checked word for word against it. Read the original

Scope

11 assets you may test, 6 excluded.

Web 1

  • https://workers.cloudflare.com

Products and areas 10

  • Durable Objects in full: runtime semantics, the storage API, alarms, and the isolation between clients and sessions talking to the same object
  • The binding layer that glues V8 to the C++ runtime, where a type or lifetime mistake crosses the JavaScript boundary
  • The bindings workerd implements for a Worker to reach other services, including service bindings, queues and the KV, R2 and D1 interfaces the runtime exposes
  • The inspector and devtools endpoint workerd opens, and the local development paths wrangler dev drives through it
  • The Node.js compatibility shims exposed under nodejs_compat, where a shim can hand back more capability than the real API would
  • The whole Workers runtime API surface: fetch, Request/Response, Headers, streams, WebSocket, the Cache API, WebCrypto, URL and text encoding, timers and everything else a Worker can call
  • The workerd server binary: process startup, socket and service wiring, and the Cap'n Proto configuration and control plane an embedder feeds untrusted config into
  • V8 isolate lifecycle management, isolate boundaries, and any state that survives a request or crosses between tenants sharing a machine
  • WebAssembly hosting inside a Worker, including the boundary between guest module and host runtime
  • workerd is one of the few Cloudflare repositories the program names on its own. The live scope table carries github.com/cloudflare/workerd as a SOURCE_CODE asset, bounty-eligible at a maximum severity of critical, with no binding to the reduced open-source row, so the default ladder up to $10,000 applies. The declaration is the repository itself rather than a hosted wrapper around it, and it covers the runtime as a whole
Out of scope (6)
  • Billing and plan-enforcement issues, which the policy caps at Low severity and a $250 maximum payout
  • Findings that require a maintainer to approve a GitHub Actions workflow before they trigger
  • Local-only wrangler dev reproductions with no demonstrated production reachability
  • Reports with no working proof of concept, which are not bounty-eligible at any severity
  • The repositories Cloudflare marks explicitly not eligible for bounty: cloudflare/vinext-private, moq-rs, privacy-gateway-server-go, saffron and recapn
  • V8 itself, which is Chrome VRP territory and already sits on the sorona.xyz paid rail as its own program

Rules

What the policy asks of you, and the bug types it won't reward, quoted from Sorona's policy. "We" in these lines means Sorona, not this site.

While testing

  • Submit through sorona.xyz first. We validate, coordinate with the program's security team, and add the payout uplift on top of whatever it awards.
  • A working proof of concept is required: no PoC, no bounty, and source-code-only analysis is Informational regardless of the severity you assign it
  • A local workerd build or wrangler dev reproduction is graded Informational unless you show the same code path is reachable in production
  • Cloudflare runs its own AI-assisted discovery and closes matching external reports as duplicates, so file early rather than polishing
  • Billing and plan-enforcement issues are capped at Low severity and $250 maximum payout however you frame them
  • The generic github.com/cloudflare catch-all scope pays a lower $250 to $3,500 band; the figures below apply because workerd is separately named

Not accepted

  • V8 itself, which is Chrome VRP territory and already sits on the sorona.xyz paid rail as its own program
  • Local-only wrangler dev reproductions with no demonstrated production reachability
  • Billing and plan-enforcement issues, which the policy caps at Low severity and a $250 maximum payout
  • Findings that require a maintainer to approve a GitHub Actions workflow before they trigger
  • Reports with no working proof of concept, which are not bounty-eligible at any severity

Summarised with AI from the program policy on Sorona, read 12 Nov 2026, and checked word for word against it. Read the original

Changes

Tracked since 11 Nov 2026. Last checked 1 hour ago.

No changes yet. When the rewards or scope move, you will see it here and in the RSS feed.

Public CVEs

Published vulnerabilities in this vendor's products, from the NVD.

Search NVD
CVESeverityPublished
CVE-2026-12523 High 7.5 14 Jul 2026
CVE-2026-2833 Critical 9.3 5 Mar 2026
CVE-2026-2835 Critical 9.3 5 Mar 2026
CVE-2026-2836 High 8.4 5 Mar 2026
CVE-2026-1229 Low 2.9 24 Feb 2026
CVE-2026-0933 High 7.7 20 Jan 2026
CVE-2025-13353 High 7.1 2 Dec 2025
CVE-2025-7054 High 8.7 7 Aug 2025
CVE-2025-4821 High 7.5 18 Jun 2025
CVE-2025-4820 Medium 5.3 18 Jun 2025
CVE-2025-6087 High 7.8 16 Jun 2025
CVE-2025-4366 High 7.4 22 May 2025
CVE-2025-4143 Medium 6.0 1 May 2025
CVE-2025-4144 Medium 5.3 1 May 2025
CVE-2021-3978 High 7.5 29 Jan 2025
CVE-2025-0651 Medium 6.1 22 Jan 2025
CVE-2024-1765 Medium 5.9 12 Mar 2024
CVE-2024-1410 Low 3.7 12 Mar 2024
CVE-2024-0212 High 8.1 29 Jan 2024
CVE-2023-6992 Medium 4.0 4 Jan 2024
CVE-2023-7078 High 7.5 29 Dec 2023
CVE-2023-7079 Medium 6.4 29 Dec 2023
CVE-2023-7080 High 8.5 29 Dec 2023
CVE-2023-6193 Medium 5.3 12 Dec 2023
CVE-2023-6180 Medium 5.3 5 Dec 2023
CVE-2023-3747 Medium 5.5 7 Sep 2023
CVE-2023-0654 Low 3.9 29 Aug 2023
CVE-2023-0238 Low 3.9 29 Aug 2023
CVE-2023-4241 High 7.5 16 Aug 2023
CVE-2023-3766 Medium 5.9 3 Aug 2023
CVE-2023-3348 Medium 5.7 3 Aug 2023
CVE-2023-2754 High 7.4 3 Aug 2023
CVE-2023-1862 High 7.3 20 Jun 2023
CVE-2023-3036 High 8.6 14 Jun 2023
CVE-2023-3040 Low 3.7 14 Jun 2023
CVE-2023-2512 Medium 6.5 12 May 2023
CVE-2023-1732 Medium 5.3 10 May 2023
CVE-2023-0652 High 7.0 6 Apr 2023
CVE-2023-1412 High 7.0 5 Apr 2023
CVE-2023-1314 High 7.5 21 Mar 2023
CVE-2022-4428 High 8.9 11 Jan 2023
CVE-2022-4457 Medium 5.5 11 Jan 2023
CVE-2014-125026 Critical 9.8 27 Dec 2022
CVE-2022-3337 Medium 6.7 28 Oct 2022
CVE-2022-3512 Medium 6.7 28 Oct 2022
CVE-2022-3321 Medium 6.7 28 Oct 2022
CVE-2022-3322 Medium 6.7 28 Oct 2022
CVE-2022-3320 Medium 6.7 28 Oct 2022
CVE-2022-3616 Medium 5.4 28 Oct 2022
CVE-2022-2529 High 7.5 30 Sep 2022
CVE-2022-2225 High 8.1 26 Jul 2022
CVE-2022-2145 Medium 5.8 28 Jun 2022
CVE-2022-2147 Medium 6.5 23 Jun 2022
CVE-2021-3907 High 7.4 11 Nov 2021
CVE-2021-3908 Medium 5.9 11 Nov 2021
CVE-2021-3909 Medium 4.4 11 Nov 2021
CVE-2021-3910 Medium 4.4 11 Nov 2021
CVE-2021-3911 Medium 4.2 11 Nov 2021
CVE-2021-3912 Medium 4.2 11 Nov 2021
CVE-2021-3761 High 7.5 9 Sep 2021

Original policy

Copied from sorona.xyz on 12 Nov 2026. The summaries on this page are made from it; the live page may have changed since.

Skip to content What this pays sorona.xyz pays 1.25× the program's reward, up to +$1,000 per finding, plus a complexity bonus of up to $1,000 for especially complex or well-chained bugs. Finding │ Program pays │ Through sorona.xyz Critical (workerd's own source-code asset, default row) │ $10,000 │ $11,000 High │ $3,000 │ $3,750 Medium │ $750 │ $938 Low │ $500 │ $625 Billing and plan-enforcement issues (capped by policy) │ $250 │ $313 Submit a vulnerability CVE history 0 Last 12 months 2 Lifetime Access control 30 % Info disclosure 25 % Code execution 25 % Denial of service 15 % Latest advisories Loading the feed Overview workerd is the actual runtime binary behind Cloudflare Workers, which serves a double-digit share of all HTTP requests on the public internet through Cloudflare's edge, and it is equally the engine under Pages Functions, Durable Objects, Workers AI gateway paths and every developer's wrangler dev . Third parties embed it independently of Cloudflare when they want a V8-isolate-per-request server, and it is the reference implementation the WinterCG/WinterTC server-side JavaScript standards track is written against. Because the isolate model is multi-tenant, a single escape is a cross-customer event, which is why Cloudflare put workerd on its own source-code scope at the default reward row, $500 at Low up to $10,000 for a Critical, rather than the reduced open-source band. sorona.xyz adds 1.25x on top of whatever Cloudflare awards, up to $1,000 more, plus a complexity bonus of up to $1,000 for a well-chained finding. Response times 10 business days First response 10 business days after first response Triage 10 business days after triage Bounty In scope workerd is one of the few Cloudflare repositories the program names on its own. The live scope table carries github.com/cloudflare/workerd as a SOURCE_CODE asset, bounty-eligible at a maximum severity of critical, with no binding to the reduced open-source row, so the default ladder up to $10,000 applies. The declaration is the repository itself rather than a hosted wrapper around it, and it covers the runtime as a whole The workerd server binary: process startup, socket and service wiring, and the Cap'n Proto configuration and control plane an embedder feeds untrusted config into The binding layer that glues V8 to the C++ runtime, where a type or lifetime mistake crosses the JavaScript boundary The whole Workers runtime API surface: fetch , Request / Response , Headers , streams, WebSocket , the Cache API, WebCrypto, URL and text encoding, timers and everything else a Worker can call V8 isolate lifecycle management, isolate boundaries, and any state that survives a request or crosses between tenants sharing a machine Durable Objects in full: runtime semantics, the storage API, alarms, and the isolation between clients and sessions talking to the same object The bindings workerd implements for a Worker to reach other services, including service bindings, queues and the KV, R2 and D1 interfaces the runtime exposes WebAssembly hosting inside a Worker, including the boundary between guest module and host runtime The Node.js compatibility shims exposed under nodejs_compat , where a shim can hand back more capability than the real API would The inspector and devtools endpoint workerd opens, and the local development paths wrangler dev drives through it Out of scope V8 itself, which is Chrome VRP territory and already sits on the sorona.xyz paid rail as its own program Local-only wrangler dev reproductions with no demonstrated production reachability The repositories Cloudflare marks explicitly not eligible for bounty: cloudflare/vinext-private , moq-rs , privacy-gateway-server-go , saffron and recapn Billing and plan-enforcement issues, which the policy caps at Low severity and a $250 maximum payout Findings that require a maintainer to approve a GitHub Actions workflow before they trigger Reports with no working proof of concept, which are not bounty-eligible at any severity Most-valued findings An isolate escape or cross-request state leak that lets one tenant's Worker read or influence another's, the finding that carries the $10,000 Critical row Durable Objects isolation failures where one client reaches another client's object state or session Code execution reachable from Worker-controlled input into the host runtime, including through the WebAssembly host boundary Access-control failures in the Cap'n Proto control plane that let untrusted configuration change what a running workerd will serve nodejs_compat shims that expose filesystem, process or network capability the Workers sandbox is supposed to withhold Any of the above shown reachable in production rather than only in a local build, which is the difference between a bounty and an Informational close Program rules Submit through sorona.xyz first. We validate, coordinate with the program's security team, and add the payout uplift on top of whatever it awards. A working proof of concept is required: no PoC, no bounty, and source-code-only analysis is Informational regardless of the severity you assign it A local workerd build or wrangler dev reproduction is graded Informational unless you show the same code path is reachable in production Cloudflare runs its own AI-assisted discovery and closes matching external reports as duplicates, so file early rather than polishing Billing and plan-enforcement issues are capped at Low severity and $250 maximum payout however you frame them The generic github.com/cloudflare catch-all scope pays a lower $250 to $3,500 band; the figures below apply because workerd is separately named Program stats 376 Reports resolved $568k Bounties paid 77% Response efficiency Disclosure Coordinated with Cloudflare on a bounded clock: nothing may be published for 90 days from submission without prior written approval. The program is unusually well documented, with published response, triage and bounty targets, so sorona.xyz files the report, tracks it against those targets, and holds publication until the window closes. Safe harbor Sorona will not pursue legal action against you for good-faith research submitted to us in line with this policy. We cannot speak for the upstream project, its vendor, or any third party, and we do not grant authorization on their behalf. You are responsible for understanding and following the laws that apply to you, wherever you are, and for staying within any scope the project has defined. Submit a vulnerability