TI-2026-08560 Aliases CVE-2026-9769 GHSA-v7cf-c9rm-wm3j

justhtml before 1.10.0 Denial of Service via deeply nested HTML

HIGH 77CWE-674Published 2026-08-23 · Updated 2026-08-24

Key facts

Attack vector: Network
Privileges required: None
User interaction: None
Attack complexity: Low
Attack requirements: None
Impact type: Denial of service
Confidentiality · integrity · availability: None · None · High
Fix status: Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA and GitHub. Impact type from CWE-674.

Summary

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 <div> 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.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV

EPSS 0.00337 27th percentileScored 2026-11-07

Fix Fixed justhtml (EmilStenstrom): 1.10.0justhtml (PyPI): 1.10.0

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: Poc
Automatable: Yes
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
EmilStenstrom	justhtml	before 1.10.0	1.10.0	Patch available	CNA
—	justhtml (PyPI)	before 1.10.0	1.10.0	Patch available	GHSA-v7cf-c9rm-wm3j

justhtml VendorEmilStenstrom Affected before 1.10.0 Fixed in 1.10.0 Patch available CNA
justhtml (PyPI) Vendor— Affected before 1.10.0 Fixed in 1.10.0 Patch available GHSA-v7cf-c9rm-wm3j

Remediation

Fix · CNA justhtml (EmilStenstrom) Fixed in 1.10.0
Fix · GHSA-v7cf-c9rm-wm3j justhtml (PyPI) Fixed in 1.10.0 Advisory →

Timeline

2026-10-02 Threatist record created from CVE-2026-9769
2026-10-03 Alias added: GHSA-v7cf-c9rm-wm3j

References

Advisory 2

Other 2

TI-2026-07422 justhtml before 1.12.0 Sanitizer Bypass via Markdown CVSS 4.0CRITICAL 9.3
TI-2026-52557 justhtml before 3.11.0 XSS via selectedcontent projection CVSS 4.0MEDIUM 5.1
TI-2026-04717 justhtml before 1.13.0 XSS via code fence breakout CVSS 4.0MEDIUM 5.1
TI-2026-06871 justhtml before 1.16.0 Multiple Security Issues via Sanitization CVSS 4.0CRITICAL 9.3
TI-2026-04716 justhtml before 1.15.0 Multiple Security Issues CVSS 4.0CRITICAL 9.3
TI-2026-04066 justhtml before 1.18.0 Denial of Service via CSS Selector CVSS 4.0HIGH 8.7

See all 10 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences