undici is an HTTP client library for Node.js. In versions 4.2.1 through 6.29.0, 7.0.0 through 7.30.0, and 8.0.0 through 8.12.1, the client process crashes when a TLS 1.2 server renegotiates after the connection is established and presents a…
Exact source revision recorded 28 Oct 2026 10:34:54 UTC. It does not establish the source's current position. Latest evidence.
euvd · EUVD-2026-102318
Publishedundici is an HTTP client library for Node.js. In versions 4.2.1 through 6.29.0, 7.0.0 through 7.30.0, and 8.0.0 through 8.12.1, the client process crashes when a TLS 1.2 server renegotiates after the connection is established and presents a different, CA-trusted certificate whose hostname does not match the requested host. Node.js re-runs hostname verification on the renegotiated handshake and destroys the socket with a certificate-altname error, but undici's established-socket error handler asserted that this error code could never occur, so the peer-controlled error became an uncaught assertion that terminates the Node.js process, affecting both the HTTP/1.1 and HTTP/2 paths. A malicious or compromised HTTPS endpoint reached through undici or the global fetch() can crash the client with a single server-initiated renegotiation, taking down all in-flight requests and background work in the process, and exploitation needs no CA compromise because the attacker controls the endpoint and can present two ordinary valid certificates. Only TLS 1.2 is affected, since TLS 1.3 does not support renegotiation. The issue is fixed in undici 6.29.1, 7.30.1, and 8.12.2, and users should upgrade to one of those versions or later. As a workaround, restrict outbound connections to TLS 1.3 so renegotiation cannot occur, when the target endpoints support it.
EUVD source date text has no stated timezone and is retained without inventing a UTC instant. Related bulletin membership is not an alias, common cause or applicability claim. A missing vector with a zero score is treated as unrated. Complete vendor/product and underlying source evidence remains in the original JSON.
Original publisher date fields
datePublished: Oct 15, 2026, 6:38:25 PM
dateUpdated: Oct 16, 2026, 8:01:29 PM
2 related source bulletins · separate from aliases
RHSA-2026:86147: Red Hat Security Advisory: Red Hat Hardened Images RPMs Security Update
CVE-2026-87018
RHSA-2026:87703: Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update
CVE-2026-87018 · CVE-2026-109383 · CVE-2026-109869 · CVE-2026-109924 · CVE-2026-109932
- Source published
- Oct 15, 2026, 6:38:25 PM (timezone not stated)
- Source modified
- Oct 16, 2026, 8:01:29 PM (timezone not stated)
- Observed here
- 28 Oct 2026 10:34:54 UTC
- Source terms
- ENISA EUVD · source terms and attribution apply
Original source record · Cite this exact observation · Complete original publisher JSON
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EUVD CVSS 3.1 · 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H