VulnerabilityPublished 12 Nov 2026Updated 13 Nov 2026

CVE-2026-123866: Nodejs · A use-after-free in Node.js HTTP/2 stream teardown can leak response memory, including the

Affects nodejsSource GCVE Database

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Authoritative record:CVE-2026-123866· High 7.5

Not known to be exploited · CVSS 7.5 High.

Data as of 13 Nov 2026, 22:04 UTC

CVSS 3.0 base score

7.5High

How severe the flaw is on the 0–10 CVSS scale.

Thin evidence

One scorer or none

CVSS scores by source
CNA (openjs)	CVSS 3.0	7.5

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: High
Integrity: None
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 11 Nov 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 13 Nov 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
Ubuntu 26.10nodejs`pkg:deb/ubuntu/nodejs?arch=source&distro=stonking`Other threats	Affected 22.22.1+dfsg+~cs22.19.15-1ubuntu1 – 24.19.0+dfsg+~cs24.13.3-1ubuntu1 4 affected builds	Fixed in–
Ubuntu 26.04 LTSnodejs`pkg:deb/ubuntu/nodejs?arch=source&distro=resolute`Other threats	Affected 20.19.4+dfsg-1 – 22.22.1+dfsg+~cs22.19.15-1ubuntu1 6 affected builds	Fixed in–
Ubuntu 24.04 LTSnodejs`pkg:deb/ubuntu/nodejs?arch=source&distro=noble`Other threats	Affected 18.13.0+dfsg1-1ubuntu2 – 18.19.1+dfsg-6ubuntu5 5 affected builds	Fixed in–
Ubuntu Pro 22.04 LTSnodejs`pkg:deb/ubuntu/nodejs?arch=source&distro=esm-apps/jammy`Other threats	Affected 12.22.5~dfsg-5ubuntu1 – 12.22.9~dfsg-1ubuntu3.6+esm2 12 affected builds	Fixed in–
Ubuntu Pro 20.04 LTSnodejs`pkg:deb/ubuntu/nodejs?arch=source&distro=esm-apps/focal`Other threats	Affected 10.15.2~dfsg-2ubuntu1 – 10.19.0~dfsg-3ubuntu1.6+esm2 10 affected builds	Fixed in–
Ubuntu Pro 18.04 LTSnodejs`pkg:deb/ubuntu/nodejs?arch=source&distro=esm-apps/bionic`Other threats	Affected 6.11.4~dfsg-1ubuntu1 – 8.10.0~dfsg-2ubuntu0.4+esm6 15 affected builds	Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

Description

A use-after-free in Node.js HTTP/2 stream teardown can leak response memory, including the contents of other connections' response buffers, to a peer. When a stream is torn down while a write is still backpressured, for example by a peer RST_STREAM or by the server's own per-stream timeout destroying the stream, the stream's response buffer is freed but a reference to it is still used, so freed or unrelated heap memory is written to the socket instead of the intended response. On Node.js 26.x and 24.x the teardown can be driven purely by a remote peer once the window-size change from 26.9.0 and 24.22.0 is present, and on all supported lines the same defect is reachable through an application-initiated teardown such as a per-stream idle timeout. This vulnerability affects Node.js 26.x, 24.x, and 22.x.

References

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