CVE-2026-109924
undici vulnerable to Denial of Service via unbounded memory in the EventSource parser
No exploitation reported by the sources we read.
- Published2026-10-15
- Fixed in8.12.2 · 7.30.1 · 6.29.1
- WeaknessCWE-770
Am I affected?
Debian, Ubuntu or Red Hat sometimes backport a fix without changing the upstream version number: such a version reads « to verify », never « affected ».With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.
Description
undici is an HTTP client library for Node.js. In versions 6.5.0 through 6.29.0, 7.0.0 through 7.30.0, and 8.0.0 through 8.12.1, its EventSource client can be driven to exhaust process memory by a malicious or compromised Server-Sent Events peer. By sending millions of tiny completed data fields with no blank event separator, or a single unfinished line split across many chunks, the parser retains a growing amount of per-field and per-chunk state that the byte-based maxEventSize and maxResponseSize limits do not bound, and because maxResponseSize is enforced on the compressed body before decompression, a small compressed response can expand into enough retained memory to terminate the process. An application only needs to maintain an EventSource connection to an untrusted peer, which controls only the response, and availability is the only impact. The issue is fixed in undici 6.29.1, 7.30.1, and 8.12.2, which bound the retained parser state independently of the byte limits, and users should upgrade to one of those versions or later. There is no workaround.
Timeline
dates in UTC- 2026-10-1519:17CVE publishedNVD
Observed activity
isMalicious corpus · updated 2026-10-23 18:48 UTCBlock these indicators
- Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2026-109924?format=txt
- CSV export: https://api.ismalicious.com/edl/cve/CVE-2026-109924?format=csv
- TAXII collection of exploited CVEs
- The EDL and CSV take an API key on the Pro plan.
Versions per branch
NVD| Branch | Affected | Fixed in | Source |
|---|---|---|---|
| 8.x | ≥ 8.0.0, < 8.12.2 | 8.12.2 | NVD |
| 7.x | ≥ 7.0.0, < 7.30.1 | 7.30.1 | NVD |
| 6.x | ≥ 6.5.0, < 6.29.1 | 6.29.1 | NVD |
as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.
Distribution builds and vendor advisories
Packages from OSV.dev and products from the vendors' CSAF advisories.
version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.
Vendor advisories
undici: undici: Denial of Service via memory exhaustion in EventSource client
cryostat/cryostat-openshift-console-plugin-rhel9 as a component of Cryostat 4 · exploit-intelligence/vulnerability-analysis-rhel9 as a component of Exploit Intelligence · amq-broker-bin.zip as a component of Red Hat AMQ Broker 7 · +110 more
Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update
Red Hat Security Advisory: Red Hat Hardened Images RPMs Security Update
Red Hat Security Advisory: Red Hat Hardened Images RPMs Security Update
Fix
- Update Nodejs undici to 8.12.2 · 7.30.1 · 6.29.1
- Vendor fix Red Hat Product Security RHSA-2026:87703 · 25 productsFor details on how to apply this update, which includes the changes described in this advisory, refer to: https://images.redhat.com/
- No fix available, says the vendor Red Hat Product Security CVE-2026-109924 · 100 productsFix deferred
- No fix available, says the vendor Red Hat Product Security CVE-2026-109924 · 10 productsAffected
- No fix planned, says the vendor Red Hat Product Security CVE-2026-109924 · 2 productsOut of support scope
- No fix planned, says the vendor Red Hat Product Security CVE-2026-109924 · 1 productWill not fix
Advisories and patches
- cna.openjsf.orgVendor Advisory
- github.comVendor Advisory
Detection
- Nuclei template
- none so far ProjectDiscovery
- Exploit-DB
- no entry Exploit-DB
- Proof-of-concept repositories
- none listed PoC-in-GitHub
Sources
Technical details
- CVSS v3 Vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Published
- 2026-10-15
- Last Modified
- 2026-10-19
- NVD status
- Analyzed
Frequently asked questions
What is CVE-2026-109924?
Is CVE-2026-109924 actively exploited?
What is the CVSS score for CVE-2026-109924?
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Related vulnerabilities
Same product first, then the same vendor advisory and the same publication week.
- CVE-2026-102276same advisory
- CVE-2026-109869same advisoryundici vulnerable to Denial of Service via unhandled error on excessive content-encodings
- CVE-2026-109932same advisoryundici WebSocket client vulnerable to Denial of Service via unbounded automatic PONG buffering
- CVE-2026-87029same advisoryundici vulnerable to Denial of Service via unhandled exception in the decompress interceptor
- CVE-2026-109841same advisoryundici vulnerable to Subresource Integrity bypass via non-lowercase algorithm tokens
- CVE-2026-87018same advisoryundici vulnerable to Denial of Service via TLS 1.2 certificate-changing renegotiation
- CVE-2026-109383same advisoryundici vulnerable to TLS certificate validation bypass via dropped tls options in Agent
- CVE-2026-109829same advisoryundici vulnerable to cache poisoning and cross-user disclosure via cross-origin redirects