CVE catalog
CVE-2026-86049
jupyter-server: CVE-2026-86049
- Severity
- High · CVSS 7.1
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:H - Published
- Source
- [NVD] · [CVE record]
- EPSS
- 0.42% · Oct 25, 2026
Jupyter Server is the backend for Jupyter web applications. Prior to version 2.21.0, the 5xx request logging path in jupyter_server/log.py copies the Referer header into a JSON header block without applying the token scrubbing used for the request URI. A request that returns HTTP 500 while the Referer contains a token-bearing URL can therefore write that token to server logs in plaintext. An attacker who can read those logs can recover the token and use the affected user's Jupyter Server permissions. This issue is fixed in version 2.21.0.
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 | jupyter-server | sid | 2.20.0-3 | vulnerable |
| Debian | jupyter-server | forky | 2.20.0-3 | vulnerable |
| Debian | jupyter-server | trixie | 2.15.0-1 | vulnerable |
| Debian | jupyter-server | bookworm | 1.23.3-1 | vulnerable |
| PyPI | jupyter-server | Not reported | 2.21.0 | fixed |
| PyPI | jupyter-server | Not reported | 2.21.0 | fixed |
Fixed-version evidence
| Distribution | Package | Type | Release | Fixed version | Urgency | Origin | Bugs |
|---|---|---|---|---|---|---|---|
| Debian | jupyter-server | source | sid | (unfixed) | not yet assigned | Not reported | [1150003] |
| Debian | jupyter-server | source | forky | (unfixed) | not yet assigned | Not reported | [1150003] |
| Debian | jupyter-server | source | trixie | (unfixed) | not yet assigned | Not reported | [1150003] |
| Debian | jupyter-server | source | bookworm | (unfixed) | not yet assigned | Not reported | [1150003] |
| PyPI | jupyter-server | PyPI | Not reported | 2.21.0 | Not reported | GHSA-C3MW-737P-C7G2 | Not reported |
| PyPI | jupyter-server | PyPI | Not reported | 2.21.0 | Not reported | PYSEC-2026-4054 | Not reported |
OpenFactory catalog packages
[Debian 12 (Bookworm)]
- [jupyter-server]Affected
Details (2)
1.23.3-1· all · bookwormAffected
dsa · jupyter-server · debian · bookworm; dsa · jupyter-server · debian · 12
1.23.3-1· all · bookwormAffected
dsa · jupyter-server · debian · bookworm; dsa · jupyter-server · debian · 12
- [python3-jupyter-server]Affected
Source package: [jupyter-server]
Details (2)
1.23.3-1· all · bookwormAffected
dsa · jupyter-server · debian · bookworm; dsa · jupyter-server · debian · 12
1.23.3-1· all · bookwormAffected
dsa · jupyter-server · debian · bookworm; dsa · jupyter-server · debian · 12
[Debian 13 (Trixie)]
- [jupyter-server]Affected
Details (2)
2.15.0-1· all · trixieAffected
dsa · jupyter-server · debian · 13
2.15.0-1· all · trixieAffected
dsa · jupyter-server · debian · 13
- [python3-jupyter-server]Affected
Source package: [jupyter-server]
Details (2)
2.15.0-1· all · trixieAffected
dsa · jupyter-server · debian · 13
2.15.0-1· all · trixieAffected
dsa · jupyter-server · debian · 13
- [python-jupyter-server-doc]Affected
Source package: [jupyter-server]
Details (2)
2.15.0-1· all · trixieAffected
dsa · jupyter-server · debian · 13
2.15.0-1· all · trixieAffected
dsa · jupyter-server · debian · 13
Observed:
References
- [https://nvd.nist.gov/vuln/detail/CVE-2026-86049]
- [https://osv.dev/vulnerability/DEBIAN-CVE-2026-86049]
- [https://osv.dev/vulnerability/PYSEC-2026-4054]
- [https://security-tracker.debian.org/tracker/CVE-2026-86049]
- [https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-86049.json]
[Debian Security Tracker] · [FIRST EPSS] · [GitHub Advisory Database] · [National Vulnerability Database (NVD)] · [OSV Package Vulnerability Database] · [Red Hat security advisories and VEX]