Nodejs: A re-entrancy flaw
Affects nodejsSource GCVE Database
Not known to be exploited · CVSS 8.1 High.
Data as of 13 Nov 2026, 22:04 UTC
Thin evidence
One scorer or none| CNA (openjs) | CVSS 3.0 | 8.1 |
|---|
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:HExploitation 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.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.10nodejspkg:deb/ubuntu/nodejs?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSnodejspkg:deb/ubuntu/nodejs?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 24.04 LTSnodejspkg:deb/ubuntu/nodejs?arch=source&distro=nobleOther threats | Affected
| Fixed in– |
Ubuntu Pro 22.04 LTSnodejspkg:deb/ubuntu/nodejs?arch=source&distro=esm-apps/jammyOther threats | Affected
| Fixed in– |
Ubuntu Pro 20.04 LTSnodejspkg:deb/ubuntu/nodejs?arch=source&distro=esm-apps/focalOther threats | Affected
| Fixed in– |
Ubuntu Pro 18.04 LTSnodejspkg:deb/ubuntu/nodejs?arch=source&distro=esm-apps/bionicOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
Description
A re-entrancy flaw in Node.js HTTPS lets an unauthenticated client read memory belonging to other connections, including TLS private keys and other users' requests. TLSWrap::DoWrite() calls ClearOut() directly when asked to write zero bytes; if that write is issued from JavaScript running inside the HTTP parser's on_body callback, ClearOut() decrypts the next TLS record while the parser is still mid-body, re-entering llhttp_execute() and causing a use-after-free and an out-of-bounds heap read. The server then copies that freed or unrelated heap memory into the response for the request body. Triggering it requires a handler that calls res.flushHeaders() before the request body ends and later calls res.end() with a non-empty chunk, and reading the leaked memory requires any ordinary route that echoes or stores a request body. Cleartext node:http is not affected. This vulnerability affects Node.js 26.x, 24.x, and 22.x.
References
- ubuntu.com/security/CVE-2026-123864 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-123864 (opens in a new tab)
- nodejs.org/en/blog/vulnerability/november-2026-security-releases (opens in a new tab)
- cna.openjsf.org/security-advisories.html (opens in a new tab)
- nodejs.org/en/blog/vulnerability/november-2026-security-releases (opens in a new tab)