# CVE-2026-9769 — EmilStenstrom justhtml

> As of 2026-08-23, CVE-2026-9769 is a HIGH-severity vulnerability in EmilStenstrom justhtml, CVSS v3.1 7.5, EPSS 0.2% (19.7th percentile). No Threadlinqs-tracked threat campaign has been attributed to CVE-2026-9769 as of 2026-08-23; the identifier is re-checked against the Threadlinqs threat corpus on every daily ingest.

**Last updated:** 2026-08-23

## What is CVE-2026-9769?

justhtml through 1.9.1 (fixed in 1.10.0) is vulnerable to uncontrolled recursion leading to denial of service. During JustHTML() construction, TreeBuilder.finish() unconditionally calls _populate_selectedcontent(), which recursively traverses the DOM tree via _find_elements()/_find_element() without a depth bound. An attacker who can supply HTML for parsing can provide deeply nested elements (e.g., ~1000 nested tags, roughly 11 KB) to exceed CPython's default recursion limit and trigger an unhandled RecursionError, which may abort parsing, fail requests, or terminate a worker/process depending on the host application's exception handling.

The record classifies CVE-2026-9769 under weakness class [CWE-674](https://intel.threadlinqs.com/cwe/CWE-674). Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs no prior authentication, needs no user interaction, and has high impact on availability. 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:** 7.5 — HIGH (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **CVSS v4.0 base score:** 8.7 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N`)
- **EPSS (FIRST):** 0.2% probability of exploitation in the next 30 days, higher than 19.7% of all scored CVEs
- **CISA KEV:** Not listed in the CISA Known Exploited Vulnerabilities catalog
- **Threadlinqs priority:** 4.5/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- **Published:** 2026-08-23

## Is CVE-2026-9769 being exploited?

It currently carries a trending score of 35 in the Threadlinqs vulnerability feed.

## Affected products and versions

- [EmilStenstrom](https://intel.threadlinqs.com/vendors/emilstenstrom): justhtml

## How to fix CVE-2026-9769

No vendor patch reference has been recorded for CVE-2026-9769 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-2026-9769

No threat campaign in the Threadlinqs corpus currently references CVE-2026-9769, 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 2026-08-24.

**Vendor advisory and patch**

- [github.com — vendor advisory](https://github.com/EmilStenstrom/justhtml/security/advisories/GHSA-v7cf-c9rm-wm3j)

**Third-party advisory**

- [vulncheck.com — third party advisory](https://www.vulncheck.com/advisories/justhtml-before-denial-of-service-via-deeply-nested-html)

Canonical: https://intel.threadlinqs.com/cve/CVE-2026-9769
Full detection coverage and IOCs for threats exploiting CVE-2026-9769 via the Threadlinqs MCP server (Purple tier): https://intel.threadlinqs.com/mcp