undici vulnerable to Denial of Service via unhandled exception in the decompress interceptor
undici is an HTTP client library for Node.js. In versions 7.15.0 through 7.30.0 and 8.0.0 through 8.12.1, its decompress interceptor forwards decompressed response data to the downstream handler from zlib stream event callbacks without catching exceptions those callbacks may throw, and while undici's engine converts a synchronous throw from a downstream handler into a per-request failure, that protection is absent when the throw happens asynchronously from a zlib callback. As a result, a downstream handler that throws by design, such as the built-in dump interceptor which throws when a response exceeds its configured maximum size, escapes as an uncaught exception that terminates the Node.js process. A malicious or compromised HTTP server can crash any client that composes the decompress interceptor with such a handler by returning a small compressed body that decompresses to more than the configured limit, so only the decompressed size matters and the bytes on the wire stay tiny. The issue is fixed in undici 7.30.1 and 8.12.2, and users should upgrade to one of those versions or later. As a workaround, avoid composing the decompress interceptor with a response handler that throws during response processing until upgrading.
CVE-2026-87029
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-87029
undici
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"vendor": "undici",
"product": "undici",
"versions": [
{
"status": "affected",
"version": "7.15.0",
"lessThan": "7.30.1",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "7.30.1",
"versionType": "semver"
},
{
"status": "affected",
"version": "8.0.0",
"lessThan": "8.12.2",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "8.12.2",
"versionType": "semver"
}
],
"packageURL": "pkg:npm/undici",
"defaultStatus": "unaffected"
}
]- Related CVEs
- CVE-2026-87029
Source reference:
/cveMetadata/cveId
Publisher severity
medium
Source reference: /containers/cna/metrics
- Event
- #34405 · Revision 1
- Added to Heist Feed
- Publisher date