fix: fetch adaptor is not enforcing max body or content length#10795
Merged
jasonsaayman merged 1 commit intov1.xfrom Apr 22, 2026
Merged
fix: fetch adaptor is not enforcing max body or content length#10795jasonsaayman merged 1 commit intov1.xfrom
jasonsaayman merged 1 commit intov1.xfrom
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2 issues found across 3 files
Confidence score: 3/5
- There is concrete regression risk in
lib/adapters/fetch.js: the maxContentLength stream-wrapping path should checkresponse.bodyfirst, otherwise no-body responses can throw a TypeError at runtime. - In
lib/helpers/estimateDataURLDecodedBytes.js, the new comment overstates behavior: thebody.lengthfallback is not strictly an upper-bound/over-count-only estimate, which can mislead future maintenance and assumptions. - Given both findings are medium severity (6/10) with high confidence (9/10), this PR has some user-impacting risk and should get a focused fix pass before merging.
- Pay close attention to
lib/adapters/fetch.jsandlib/helpers/estimateDataURLDecodedBytes.js- runtime no-body handling and inaccurate safety-property documentation need correction.
Prompt for AI agents (unresolved issues)
Check if these issues are valid — if so, understand the root cause of each and fix them. If appropriate, use sub-agents to investigate and fix each issue separately.
<file name="lib/helpers/estimateDataURLDecodedBytes.js">
<violation number="1" location="lib/helpers/estimateDataURLDecodedBytes.js:77">
P2: Custom agent: **Flag AI Slop and Fabricated Changes**
Added comment claims a safety property (“upper-bound” / “over-counting only”) that the `body.length` fallback does not provide.</violation>
</file>
<file name="lib/adapters/fetch.js">
<violation number="1" location="lib/adapters/fetch.js:315">
P2: Guard the maxContentLength stream-wrapping path with `response.body` to avoid TypeError on no-body responses.</violation>
</file>
Reply with feedback, questions, or to request a fix. Tag @cubic-dev-ai to re-run a review.
| } | ||
|
|
||
| // Browser/worker fallback: use TextEncoder when available, else fall back to | ||
| // raw string length as an upper-bound heuristic. Both are safe for a DoS |
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P2: Custom agent: Flag AI Slop and Fabricated Changes
Added comment claims a safety property (“upper-bound” / “over-counting only”) that the body.length fallback does not provide.
Prompt for AI agents
Check if this issue is valid — if so, understand the root cause and fix it. At lib/helpers/estimateDataURLDecodedBytes.js, line 77:
<comment>Added comment claims a safety property (“upper-bound” / “over-counting only”) that the `body.length` fallback does not provide.</comment>
<file context>
@@ -69,5 +69,16 @@ export default function estimateDataURLDecodedBytes(url) {
+ }
+
+ // Browser/worker fallback: use TextEncoder when available, else fall back to
+ // raw string length as an upper-bound heuristic. Both are safe for a DoS
+ // guard (over-counting only makes the check stricter for non-ASCII content).
+ if (typeof TextEncoder === 'function') {
</file context>
| if (supportsResponseStream && (onDownloadProgress || (isStreamResponse && unsubscribe))) { | ||
| if ( | ||
| supportsResponseStream && | ||
| (onDownloadProgress || hasMaxContentLength || (isStreamResponse && unsubscribe)) |
Contributor
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P2: Guard the maxContentLength stream-wrapping path with response.body to avoid TypeError on no-body responses.
Prompt for AI agents
Check if this issue is valid — if so, understand the root cause and fix it. At lib/adapters/fetch.js, line 315:
<comment>Guard the maxContentLength stream-wrapping path with `response.body` to avoid TypeError on no-body responses.</comment>
<file context>
@@ -252,10 +293,27 @@ const factory = (env) => {
- if (supportsResponseStream && (onDownloadProgress || (isStreamResponse && unsubscribe))) {
+ if (
+ supportsResponseStream &&
+ (onDownloadProgress || hasMaxContentLength || (isStreamResponse && unsubscribe))
+ ) {
const options = {};
</file context>
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Summary by cubic
Enforces
maxBodyLengthandmaxContentLengthin thefetchadapter with pre-checks, streaming checks, and data: URL guards to match the Node HTTP adapter and prevent oversized payloads.Description
maxBodyLengthbefore dispatch for non-GET/HEAD requests; emitERR_BAD_REQUEST.Content-Lengthand reject early if it exceedsmaxContentLength; emitERR_BAD_RESPONSE.data:URLs by estimating decoded size before materializing.ReadableStream.estimateDataURLDecodedByteswith browser-safe fallbacks (TextEncoder/string length).fetchadapter was not enforcing size limits; this aligns behavior with the HTTP adapter and docs.ERR_BAD_REQUEST(request body),ERR_BAD_RESPONSE(response/content).Docs
/docs/to note thefetchadapter now respectsmaxBodyLengthandmaxContentLength, including:Content-Length, streaming enforcement, anddata:URL behavior.Testing
tests/unit/adapters/fetch.test.js:maxBodyLength.Content-LengthexceedsmaxContentLength.data:URLs (base64 and plain).Semantic version impact
fetchadapter with documented/expected limits. Potentially stricter behavior if limits were previously set but unenforced.Written for commit 600048c. Summary will update on new commits.