CVE-2026-65902: DOMPurify before 3.4.7 Hook Mutation Pollution via allowedTags
Vulnerability summary
CVE-2026-65902 is a medium (CVSS 6.1) Trust Boundary Violation vulnerability in cure53 dompurify. EPSS estimates a 0.36% chance of exploitation in the next 30 days, higher than 29.2% of scored vulnerabilities. 1 public exploit is recorded.
Not severe (CVSS 5.3, network access); no exploitation reported by the 5 checked sources
Source freshness unavailable
How is this decided?Advisory lineage
Upstream 0 · Downstream 2 · Related 1Timeline
- 23-07-2026PublishedVulnerability first disclosed.
- 29-10-2026Last modifiedVulnerability information updated.
Description
DOMPurify before 3.4.7 passes direct references to the module-level DEFAULT_ALLOWED_TAGS and DEFAULT_ALLOWED_ATTR sets to the uponSanitizeElement and uponSanitizeAttribute hooks via data.allowedTags / data.allowedAttributes when sanitize is called without an explicit cfg.ALLOWED_TAGS / cfg.ALLOWED_ATTR array. A hook that mutates these fields permanently widens the default allow-lists for the lifetime of the DOMPurify instance, so all subsequent default-config sanitize calls inherit the widened defaults and attacker payloads using the poisoned tag/attribute name survive sanitization. removeAllHooks(), clearConfig(), and passing a fresh cfg do not recover the state; only constructing a new DOMPurify instance does.
CVSS metrics
10 scores · 7 sources · 2 versions- OSV · UbuntuEcosystem advisory · calculated5.3MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N
- OSV · DebianEcosystem advisory · calculated5.3MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/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
- OSV · WolfiEcosystem advisory · calculated5.3MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N
- OSV · ChainguardEcosystem advisory · calculated5.3MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N
- NVDNIST5.3MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/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
- OSV · UbuntuEcosystem advisory · calculated6.1MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
- OSV · NpmEcosystem advisory · calculated6.1MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
- NVDNIST6.1MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
EPSS trend
Probability
0.36%
Chance of exploitation in the next 30 days
Percentile
29%
Versus all other CVEs
30-day change
No change 0.00 pp
From 0.36% on 04-10-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
1 foundDompurify
Maturity: poc
Weaknesses
CWE · root causeAffected systems
Known conditions: network-reachable, no authentication, user interaction (CVSS vector). Other conditions: not stated in public data.
Chainguard50 products
- airflow-2All versions (No fix recorded)
- airflow-core-2All versions (No fix recorded)
- gitlab-rails-ce-18.1All versions (No fix recorded)
- gitlab-rails-ce-18.10All versions (No fix recorded)
- gitlab-rails-ce-18.11All versions (No fix recorded) | < 18.11.13-r0
Wolfi4 products
- langfuse-3-compat< 3.225.7-r6
- langfuse-3-worker< 3.191.0-r0
- nextcloud-server-32< 32.0.12-r0
- nextcloud-server-33< 33.0.6-r0
Cure531 product
- dompurify< 3.4.7
Debian1 product
- node-dompurifyAll versions (No fix recorded) | < 3.4.12+dfsg-1
Npm1 product
- dompurify< 3.4.7
Ubuntu1 product
- node-dompurifyAll versions (No fix recorded)
6 vendors · 58 products
References
9 links- github.com/cure53/DOMPurify/security/advisories/GHSA-76mc-f452-cxcmVendor AdvisoryREPORTAdvisoryWEBExploitThird Party Advisory
- www.vulncheck.com/advisories/dompurify-before-hook-mutation-pollution-via-allowedtagsThird Party AdvisoryAdvisory
- github.com/cure53/DOMPurifyPACKAGE