CVE-2026-35536: Jupyterlab · Tornado has incomplete validation of cookie attributes
Affects jupyterlabSource GCVE Database
Not known to be exploited · CVSS 7.2 High : upgrade to 4.5.6 soon.
Data as of 30 Oct 2026, 08:59 UTC
- Patch
- Available – fixed in 4.5.6
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:NExploitation evidence
Disclosed: evidence found.
CVE published 3 Apr 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 29 Oct 2026.
What to do
Upgrade jupyterlab to 4.5.6.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Homebrewjupyterlabpkg:brew/jupyterlabOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
Upgrade JupyterLab to version 4.5.6 or later, which includes the fix for this vulnerability. Since a patch is available and the fixed version is explicitly identified, applying this update is the recommended remediation.
Description
A vulnerability in Tornado used by JupyterLab versions 1.2.0 up to but not including 4.5.6 allows incomplete validation of cookie attributes in the set_cookie method. Specifically, the domain, path, and samesite arguments were not fully validated, permitting semicolons that could enable injection of attacker-controlled cookie attributes. This flaw is fixed in version 4.5.6.
References
- github.com/tornadoweb/tornado/security/advisories/GHSA-78cv-mqj4-43f7 (opens in a new tab)
- github.com/tornadoweb/tornado/commit/24a2d96ea115f663b223887deb0060f13974c104 (opens in a new tab)
- github.com/tornadoweb/tornado (opens in a new tab)
- github.com/tornadoweb/tornado/releases/tag/v6.5.5 (opens in a new tab)