CVE-2026-73374
Stored Cross-Site Scripting (XSS) via Unescaped CNA Reference Tags in vulnerability-lookup
A stored cross-site scripting (XSS) vulnerability existed in Vulnerability-Lookup in the render_tag_badges Jinja filter used to display reference tags associated with vulnerability records.
Values from containers.cna.references[].tags[] were directly interpolated into HTML badge elements and the resulting string was wrapped in markupsafe.Markup. Because Markup marks the generated content as safe, Jinja's automatic HTML escaping was bypassed.
An authenticated user with permissions to create or modify vulnerability records, such as a user holding the vulnerability:create or vulnerability:modify permission, could submit a crafted reference tag through the CNA API containing arbitrary HTML or JavaScript-capable markup.
The malicious value would subsequently be stored as part of the vulnerability record. When another user visited the corresponding public /cve/<id> or /vuln/<id> page, the crafted tag would be rendered as HTML in the viewer's browser. This could result in JavaScript execution in the security context of the Vulnerability-Lookup application.
Successful exploitation could allow an attacker to perform actions in the context of a victim, access information available to the victim's browser session, or modify page content. As the affected vulnerability pages can be accessed publicly, exploitation may affect users who are not authenticated.
The issue was corrected by applying markupsafe.escape() to each reference tag before inserting it into the HTML badge markup, while retaining Markup only for the static HTML scaffolding.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- Active
What an attacker can affect
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
6.1
Stored Cross-Site Scripting (XSS) via Unescaped CNA Reference Tags in vulnerability-lookup
A stored cross-site scripting (XSS) vulnerability existed in Vulnerability-Lookup in the render_tag_badges Jinja filter used to display reference tags associated with vulnerability records.
Values from containers.cna.references[].tags[] were directly interpolated into HTML badge elements and the resulting string was wrapped in markupsafe.Markup. Because Markup marks the generated content as safe, Jinja's automatic HTML escaping was bypassed.
An authenticated user with permissions to create or modify vulnerability records, such as a user holding the vulnerability:create or vulnerability:modify permission, could submit a crafted reference tag through the CNA API containing arbitrary HTML or JavaScript-capable markup.
The malicious value would subsequently be stored as part of the vulnerability record. When another user visited the corresponding public /cve/<id> or /vuln/<id> page, the crafted tag would be rendered as HTML in the viewer's browser. This could result in JavaScript execution in the security context of the Vulnerability-Lookup application.
Successful exploitation could allow an attacker to perform actions in the context of a victim, access information available to the victim's browser session, or modify page content. As the affected vulnerability pages can be accessed publicly, exploitation may affect users who are not authenticated.
The issue was corrected by applying markupsafe.escape() to each reference tag before inserting it into the HTML badge markup, while retaining Markup only for the static HTML scaffolding.
- Record
CVE-2026-73374- CVSS 4.0
- 6.1 Medium
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:L/VA:N/SC:H/SI:N/SA:N - Weakness
- CWE-79
- Updated
- 2026-11-02
EUVDEUVD-2026-57219
6.1
A stored cross-site scripting (XSS) vulnerability existed in Vulnerability-Lookup in the render_tag_badges Jinja filter used to display reference tags associated with vulnerability records.
Values from containers.cna.references[].tags[] were directly interpolated into HTML badge elements and the resulting string was wrapped in markupsafe.Markup. Because Markup marks the generated content as safe, Jinja's automatic HTML escaping was bypassed.
An authenticated user with permissions to create or modify vulnerability records, such as a user holding the vulnerability:create or vulnerability:modify permission, could submit a crafted reference tag through the CNA API containing arbitrary HTML or JavaScript-capable markup.
The malicious value would subsequently be stored as part of the vulnerability record. When another user visited the corresponding public /cve/<id> or /vuln/<id> page, the crafted tag would be rendered as HTML in the viewer's browser. This could result in JavaScript execution in the security context of the Vulnerability-Lookup application.
Successful exploitation could allow an attacker to perform actions in the context of a victim, access information available to the victim's browser session, or modify page content. As the affected vulnerability pages can be accessed publicly, exploitation may affect users who are not authenticated.
The issue was corrected by applying markupsafe.escape() to each reference tag before inserting it into the HTML badge markup, while retaining Markup only for the static HTML scaffolding.
- Record
EUVD-2026-57219- CVSS 4.0
- 6.1 Medium
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:L/VA:N/SC:H/SI:N/SA:N - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-xx2h-7258-xw7c
6.1
A stored cross-site scripting (XSS) vulnerability existed in Vulnerability-Lookup in the...
A stored cross-site scripting (XSS) vulnerability existed in Vulnerability-Lookup in the render_tag_badges Jinja filter used to display reference tags associated with vulnerability records.
Values from containers.cna.references[].tags[] were directly interpolated into HTML badge elements and the resulting string was wrapped in markupsafe.Markup. Because Markup marks the generated content as safe, Jinja's automatic HTML escaping was bypassed.
An authenticated user with permissions to create or modify vulnerability records, such as a user holding the vulnerability:create or vulnerability:modify permission, could submit a crafted reference tag through the CNA API containing arbitrary HTML or JavaScript-capable markup.
The malicious value would subsequently be stored as part of the vulnerability record. When another user visited the corresponding public /cve/<id> or /vuln/<id> page, the crafted tag would be rendered as HTML in the viewer's browser. This could result in JavaScript execution in the security context of the Vulnerability-Lookup application.
Successful exploitation could allow an attacker to perform actions in the context of a victim, access information available to the victim's browser session, or modify page content. As the affected vulnerability pages can be accessed publicly, exploitation may affect users who are not authenticated.
The issue was corrected by applying markupsafe.escape() to each reference tag before inserting it into the HTML badge markup, while retaining Markup only for the static HTML scaffolding.
- Record
GHSA-xx2h-7258-xw7c- CVSS 4.0
- 6.1 Medium
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:L/VA:N/SC:H/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - Weakness
- CWE-79
- Updated
- 2026-11-02
NVD
6.1
A stored cross-site scripting (XSS) vulnerability existed in Vulnerability-Lookup in the render_tag_badges Jinja filter used to display reference tags associated with vulnerability records.
Values from containers.cna.references[].tags[] were directly interpolated into HTML badge elements and the resulting string was wrapped in markupsafe.Markup. Because Markup marks the generated content as safe, Jinja's automatic HTML escaping was bypassed.
An authenticated user with permissions to create or modify vulnerability records, such as a user holding the vulnerability:create or vulnerability:modify permission, could submit a crafted reference tag through the CNA API containing arbitrary HTML or JavaScript-capable markup.
The malicious value would subsequently be stored as part of the vulnerability record. When another user visited the corresponding public /cve/<id> or /vuln/<id> page, the crafted tag would be rendered as HTML in the viewer's browser. This could result in JavaScript execution in the security context of the Vulnerability-Lookup application.
Successful exploitation could allow an attacker to perform actions in the context of a victim, access information available to the victim's browser session, or modify page content. As the affected vulnerability pages can be accessed publicly, exploitation may affect users who are not authenticated.
The issue was corrected by applying markupsafe.escape() to each reference tag before inserting it into the HTML badge markup, while retaining Markup only for the static HTML scaffolding.
- Record
CVE-2026-73374- CVSS 4.0
- 6.1 Medium
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:L/VA:N/SC:H/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - Weakness
- CWE-79
- Updated
- 2026-11-02
OSV
6.1
Stored Cross-Site Scripting (XSS) via Unescaped CNA Reference Tags in vulnerability-lookup
A stored cross-site scripting (XSS) vulnerability existed in Vulnerability-Lookup in the render_tag_badges Jinja filter used to display reference tags associated with vulnerability records.
Values from containers.cna.references[].tags[] were directly interpolated into HTML badge elements and the resulting string was wrapped in markupsafe.Markup. Because Markup marks the generated content as safe, Jinja's automatic HTML escaping was bypassed.
An authenticated user with permissions to create or modify vulnerability records, such as a user holding the vulnerability:create or vulnerability:modify permission, could submit a crafted reference tag through the CNA API containing arbitrary HTML or JavaScript-capable markup.
The malicious value would subsequently be stored as part of the vulnerability record. When another user visited the corresponding public /cve/<id> or /vuln/<id> page, the crafted tag would be rendered as HTML in the viewer's browser. This could result in JavaScript execution in the security context of the Vulnerability-Lookup application.
Successful exploitation could allow an attacker to perform actions in the context of a victim, access information available to the victim's browser session, or modify page content. As the affected vulnerability pages can be accessed publicly, exploitation may affect users who are not authenticated.
The issue was corrected by applying markupsafe.escape() to each reference tag before inserting it into the HTML badge markup, while retaining Markup only for the static HTML scaffolding.
- Record
CVE-2026-73374- CVSS 4.0
- 6.1 Medium
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:L/VA:N/SC:H/SI:N/SA:N - Weakness
- CWE-79
- Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-73374 is a medium vulnerability (CVSS 6.1) in Circl Vulnerability-lookup, published August 12, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.57%, the 47th percentile. No source names a fixed version.
References
github.com/vulnerability-lookup/vulnerability-lookup/commit/d29901655c50cf3c25737d9ea86180268df51b57
nvd.nist.gov/vuln/detail/CVE-2026-73374
github.com/advisories/GHSA-xx2h-7258-xw7c
github.com/CVEProject/cvelistV5/tree/main/cves/2026/73xxx/CVE-2026-73374.json
github.com/vulnerability-lookup/vulnerability-lookup