CVE catalog

CVE-2026-12151

Severity: High · CVSS 7.5CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Published: Jun 17, 2026, 4:05:38 PM UTC
Source: [NVD] · [CVE record]
EPSS: 0.79% · Oct 27, 2026

Impact: The undici WebSocket client enforces maxPayloadSize on the cumulative byte count of fragments in a message but does not enforce a limit on the number of fragments. A malicious WebSocket server can stream many small or empty continuation frames that each pass per-frame and cumulative-size validation, collectively causing unbounded memory growth in the client process. The result is memory exhaustion and a denial of service. Affected applications are those using the undici WebSocket client (new WebSocket(...)) or the WebSocketStream API that can be induced to connect to an attacker-controlled or compromised WebSocket endpoint. All releases starting at undici 6.17.0 are affected. Patches: Upgrade to undici >= 6.26.0, >= 7.28.0, or >= 8.5.0. Workarounds: No workaround is available. The fix must be applied through an upgrade.

Vulnerable and fixed packages

Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.

Distribution	Package	Release	Version	Status
Debian	node-undici	sid	`8.12.2+dfsg+~cs3.2.3-2`	fixed
Debian	node-undici	forky	`8.10.2+dfsg+~cs3.2.2-1`	fixed
Debian	node-undici	trixie	`7.3.0+dfsg1+~cs24.12.11-1`	vulnerable
Debian	node-undici	bookworm	`5.15.0+dfsg1+~cs20.10.9.3-1+deb12u4`	vulnerable
Debian	node-undici	bookworm-security	`5.15.0+dfsg1+~cs20.10.9.3-1+deb12u3`	vulnerable
Cpe	node-undici	Not reported	Not reported	vulnerable
Cpe	undici	Not reported	`6.27.0`	fixed
Cpe	undici	Not reported	`7.28.0`	fixed
Cpe	undici	Not reported	`8.5.0`	fixed
Cpe	undici	Not reported	`8.5.0`	fixed

Fixed-version evidence

Distribution	Package	Type	Release	Fixed version	Urgency	Origin	Bugs
Debian	node-undici	source	sid	`8.5.0+dfsg+~cs3.2.0-1`	not yet assigned	Not reported	[1140363]
Debian	node-undici	source	forky	`8.5.0+dfsg+~cs3.2.0-1`	not yet assigned	Not reported	[1140363]
Debian	node-undici	source	trixie	`(unfixed)`	not yet assigned	Not reported	[1140363]
Debian	node-undici	source	bookworm	`(unfixed)`	not yet assigned	Not reported	[1140363]
Cpe	undici	cpe	Not reported	`6.27.0`	Not reported	Not reported	Not reported
Cpe	undici	cpe	Not reported	`7.28.0`	Not reported	Not reported	Not reported
Cpe	undici	cpe	Not reported	`8.5.0`	Not reported	Not reported	Not reported
Cpe	undici	cpe	Not reported	`8.5.0`	Not reported	NVD-CVE-2026-12151	Not reported

[Debian bug #1140363]

Notes

[trixie] node-undici: Minor issue [bookworm] node-undici: Minor issue; requires connecting to an attacker-controlled WebSocket endpoint, and the WebSocket API is experimental in 5.15.0

OpenFactory catalog packages

[Debian 12 (Bookworm)]

[node-llhttp]Affected
Source package: [node-undici]
Details (4)
- 8.1.0~5.15.0+dfsg1+~cs20.10.9.3-1+deb12u4 · all · bookworm
  Affected
  nvd · node-undici · debian · bookworm; nvd · node-undici · debian · 12
- 8.1.0~5.15.0+dfsg1+~cs20.10.9.3-1+deb12u4 · all · bookworm
  Affected
  nvd · node-undici · debian · bookworm; nvd · node-undici · debian · 12
- 8.1.0~5.15.0+dfsg1+~cs20.10.9.3-1+deb12u3 · all · bookworm-security
  Affected
  nvd · node-undici · debian · bookworm; nvd · node-undici · debian · 12
- 8.1.0~5.15.0+dfsg1+~cs20.10.9.3-1+deb12u3 · all · bookworm-security
  Affected
  nvd · node-undici · debian · bookworm; nvd · node-undici · debian · 12
[node-undici]Affected
Details (4)
- 5.15.0+dfsg1+~cs20.10.9.3-1+deb12u4 · all · bookworm
  Affected
  nvd · node-undici · debian · bookworm; nvd · node-undici · debian · 12
- 5.15.0+dfsg1+~cs20.10.9.3-1+deb12u4 · all · bookworm
  Affected
  nvd · node-undici · debian · bookworm; nvd · node-undici · debian · 12
- 5.15.0+dfsg1+~cs20.10.9.3-1+deb12u3 · all · bookworm-security
  Affected
  nvd · node-undici · debian · bookworm; nvd · node-undici · debian · 12
- 5.15.0+dfsg1+~cs20.10.9.3-1+deb12u3 · all · bookworm-security
  Affected
  nvd · node-undici · debian · bookworm; nvd · node-undici · debian · 12

[Debian 13 (Trixie)]

[libllhttp9.2]Affected
Source package: [node-undici]
Details (2)
- 9.2.1~7.3.0+dfsg1+~cs24.12.11-1 · amd64 · trixie
  Affected
  nvd · node-undici · debian · 13
- 9.2.1~7.3.0+dfsg1+~cs24.12.11-1 · arm64 · trixie
  Affected
  nvd · node-undici · debian · 13
[libllhttp-dev]Affected
Source package: [node-undici]
Details (2)
- 9.2.1~7.3.0+dfsg1+~cs24.12.11-1 · amd64 · trixie
  Affected
  nvd · node-undici · debian · 13
- 9.2.1~7.3.0+dfsg1+~cs24.12.11-1 · arm64 · trixie
  Affected
  nvd · node-undici · debian · 13
[node-llhttp]Affected
Source package: [node-undici]
Details (2)
- 9.2.1~7.3.0+dfsg1+~cs24.12.11-1 · all · trixie
  Affected
  nvd · node-undici · debian · 13
- 9.2.1~7.3.0+dfsg1+~cs24.12.11-1 · all · trixie
  Affected
  nvd · node-undici · debian · 13
[node-undici]Affected
Details (2)
- 7.3.0+dfsg1+~cs24.12.11-1 · all · trixie
  Affected
  nvd · node-undici · debian · 13
- 7.3.0+dfsg1+~cs24.12.11-1 · all · trixie
  Affected
  nvd · node-undici · debian · 13

Observed: Oct 23, 2026, 9:45:35 PM UTC

References

[CERT-Bund public advisories] · [Debian Security Tracker] · [FIRST EPSS] · [National Vulnerability Database (NVD)] · [OSV Package Vulnerability Database] · [Red Hat security advisories and VEX] · [SUSE security advisories and VEX]