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Vulnerability details: VCID-7fb7-sbm9-u7fa
Vulnerability ID VCID-7fb7-sbm9-u7fa
Aliases CVE-2026-33889
GHSA-97v6-998m-fp4g
Summary ApostropheCMS is an open-source Node.js content management system. Versions 4.28.0 and prior contain a stored cross-site scripting vulnerability in the @apostrophecms/color-field module, where color values prefixed with -- bypass TinyColor validation intended for CSS custom properties, and the launder.string() call performs only type coercion without stripping HTML metacharacters. These unsanitized values are then concatenated directly into <style> tags both in per-widget style elements rendered for all visitors and in the global stylesheet rendered for editors, with the output marked as safe HTML. An editor can inject a value which closes the style tag and executes arbitrary JavaScript in the browser of every visitor to any page containing the affected widget. This enables mass session hijacking, cookie theft, and privilege escalation to administrative control if an admin views draft content. This issue has been fixed in version 4.29.0.
Status Published
Exploitability 0.5
Weighted Severity 6.2
Risk 3.1
Affected and Fixed Packages Package Details
Weaknesses (3)
CWE-79 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CWE-937 OWASP Top Ten 2013 Category A9 - Using Components with Known Vulnerabilities
CWE-1035 OWASP Top Ten 2017 Category A9 - Using Components with Known Vulnerabilities
System Score Found at
epss 0.00014 https://api.first.org/data/v1/epss?cve=CVE-2026-33889
epss 0.00014 https://api.first.org/data/v1/epss?cve=CVE-2026-33889
cvssv3.1_qr MODERATE https://github.com/advisories/GHSA-97v6-998m-fp4g
cvssv3.1 5.4 https://github.com/apostrophecms/apostrophe
generic_textual MODERATE https://github.com/apostrophecms/apostrophe
cvssv3.1 5.4 https://github.com/apostrophecms/apostrophe/commit/6a89bdb7acdb2e1e9bf1429961a6ba7f99410481
generic_textual MODERATE https://github.com/apostrophecms/apostrophe/commit/6a89bdb7acdb2e1e9bf1429961a6ba7f99410481
ssvc Track https://github.com/apostrophecms/apostrophe/commit/6a89bdb7acdb2e1e9bf1429961a6ba7f99410481
cvssv3.1 5.4 https://github.com/apostrophecms/apostrophe/security/advisories/GHSA-97v6-998m-fp4g
cvssv3.1_qr MODERATE https://github.com/apostrophecms/apostrophe/security/advisories/GHSA-97v6-998m-fp4g
generic_textual MODERATE https://github.com/apostrophecms/apostrophe/security/advisories/GHSA-97v6-998m-fp4g
ssvc Track https://github.com/apostrophecms/apostrophe/security/advisories/GHSA-97v6-998m-fp4g
cvssv3.1 5.4 https://nvd.nist.gov/vuln/detail/CVE-2026-33889
generic_textual MODERATE https://nvd.nist.gov/vuln/detail/CVE-2026-33889
Reference id Reference type URL
https://api.first.org/data/v1/epss?cve=CVE-2026-33889
https://github.com/apostrophecms/apostrophe
https://nvd.nist.gov/vuln/detail/CVE-2026-33889
6a89bdb7acdb2e1e9bf1429961a6ba7f99410481 https://github.com/apostrophecms/apostrophe/commit/6a89bdb7acdb2e1e9bf1429961a6ba7f99410481
GHSA-97v6-998m-fp4g https://github.com/advisories/GHSA-97v6-998m-fp4g
GHSA-97v6-998m-fp4g https://github.com/apostrophecms/apostrophe/security/advisories/GHSA-97v6-998m-fp4g
No exploits are available.
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N Found at https://github.com/apostrophecms/apostrophe
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N Found at https://github.com/apostrophecms/apostrophe/commit/6a89bdb7acdb2e1e9bf1429961a6ba7f99410481
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: SSVCv2/E:P/A:N/T:P/P:M/B:A/M:M/D:T/2026-04-16T11:26:46Z/ Found at https://github.com/apostrophecms/apostrophe/commit/6a89bdb7acdb2e1e9bf1429961a6ba7f99410481
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N Found at https://github.com/apostrophecms/apostrophe/security/advisories/GHSA-97v6-998m-fp4g
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: SSVCv2/E:P/A:N/T:P/P:M/B:A/M:M/D:T/2026-04-16T11:26:46Z/ Found at https://github.com/apostrophecms/apostrophe/security/advisories/GHSA-97v6-998m-fp4g
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N Found at https://nvd.nist.gov/vuln/detail/CVE-2026-33889
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Exploit Prediction Scoring System (EPSS)
Percentile 0.02501
EPSS Score 0.00014
Published At June 11, 2026, 12:55 p.m.
Date Actor Action Source VulnerableCode Version
2026-06-11T16:49:29.641496+00:00 Vulnrichment Import https://github.com/cisagov/vulnrichment/blob/develop/2026/33xxx/CVE-2026-33889.json 38.6.0