Security readout for executives and security teams
Plain-English summary
This issue lets a crafted link that appears to point to a trusted Jupyter Server send a user to another website. Business impact is mainly phishing, spoofing, and user-trust abuse rather than direct server compromise. The cited sources do not show active exploitation.
Executive priority
Handle in normal patch cycles unless Jupyter Server hosts are public, high-trust, or used by sensitive teams. Prioritize faster remediation where phishing against researchers, analysts, or administrators would create business risk.
Technical view
Jupyter Server versions before 1.0.6 contain a CWE-601 open redirect. Exploitation requires a user to follow a crafted link and is most practical when the attacker knows a real Jupyter Server host. CVSS 3.1 is 4.1 with low attack complexity, required user interaction, and changed scope.
Likely exposure
Systems running jupyter_server before 1.0.6 are affected. Exposure is higher where Jupyter Server hostnames are known to users, partners, or the public, because crafted links can look legitimate before redirecting elsewhere.
Exploitation context
The bundle marks CISA KEV as false and provides no evidence of active exploitation. The plausible abuse case is social engineering: a user clicks a link that seems to target a familiar Jupyter Server but lands on a spoofed public site.
Researcher notes
The vulnerability is an open redirect, not a direct code execution issue. The advisory states all Jupyter Servers are technically affected, but practical attack construction depends on knowing a host. The source bundle does not include exploit code, observed exploitation, or alternative mitigations beyond the fixed release.
Mitigation direction
- Upgrade jupyter_server to version 1.0.6 or later.
- Review the GitHub advisory and changelog before rollout.
- Inventory externally known Jupyter Server hosts.
- Educate users to treat unexpected notebook links cautiously.
Validation and detection
- Check dependency manifests or runtime package inventory for jupyter_server versions.
- Flag any jupyter_server instance below 1.0.6.
- Confirm whether Jupyter Server hostnames are public or broadly shared.
- Review vendor advisory references for environment-specific guidance.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-601: User-session and phishing behavior lookup
Client-side and session-facing weaknesses should be reviewed alongside initial-access and user-execution behaviors. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2020-26232 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Medium
- CVSS
- 4.1 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:N/I:L/A:N
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:N/I:L/A:N2.31.4Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
4.1MediumVector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:N/I:L/A:N
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/jupyter/jupyter_server/security/advisories/GHSA-grfj-wjv9-4f9vCVE reference · x_refsource_CONFIRM
- https://github.com/jupyter-server/jupyter_server/commit/3d83e49090289c431da253e2bdb8dc479cbcb157CVE reference · x_refsource_MISC
- https://github.com/jupyter-server/jupyter_server/blob/master/CHANGELOG.md#106---2020-11-18CVE reference · x_refsource_MISC
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
URL Redirection to Untrusted Site ('Open Redirect')
URL Redirection to Untrusted Site ('Open Redirect') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.