What is CVE-2026-8630?
justhtml before 1.12.0 (versions and . When a DOM tree is processed by sanitize_dom() using a custom policy that keeps these elements, text nodes inside them are serialized literally without escaping, allowing attacker-controlled text containing the matching closing tag sequence to break out of the raw-text context and inject arbitrary HTML into the serialized output. The default sanitization policy is not affected because it drops the contents of style and script.
The record classifies CVE-2026-8630 under weakness class CWE-79. Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs no prior authentication, needs a user to take an action first. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 43 days ago.
Severity and exploitation probability
- CVSS v3.1 base score
- 6.1 — MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N - CVSS v4.0 base score
- 5.1
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N - EPSS (FIRST)
- 0.1% probability of exploitation in the next 30 days, higher than 8.4% of all scored CVEs
- CISA KEV
- Not listed in the CISA Known Exploited Vulnerabilities catalog
- Threadlinqs priority
- 3.4/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- Published
- 2026-08-23
Is CVE-2026-8630 being exploited?
It currently carries a trending score of 32 in the Threadlinqs vulnerability feed.
Affected products and versions
- EmilStenstrom: justhtml
How to fix CVE-2026-8630
No vendor patch reference has been recorded for CVE-2026-8630 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.
Threat activity tracking CVE-2026-8630
No threat campaign in the Threadlinqs corpus currently references CVE-2026-8630, in its CVE list or as an indicator. The linkage is recomputed from the live corpus on every daily ingest, so this section fills in as soon as a tracked campaign cites the identifier.
Sources
Enriched from CVE.org, FIRST EPSS, GitHub Security Advisories. Last verified by Threadlinqs on .