CVE-2026-15308: The incremental HTML parser (html.parser.HTMLParser) allows for CPU denial-of-service through repeated unterminated markup declarations when processing uncontrolled data.

highCVSS 7.5CVE-2026-15308

The incremental HTML parser (html.parser.HTMLParser) allows for CPU denial-of-service through repeated unterminated markup declarations when processing uncontrolled data.

Details

Source: NVD Recent CVEs (US · database · site)
Severity: high — CVSS 7.5
Published: 2026-07-09
Last updated: 2026-07-10
Exploitation: Not in CISA KEV at last sync

Original advisory: https://nvd.nist.gov/vuln/detail/CVE-2026-15308

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Low exploitation riskCVE-2026-153080.53% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 41% of all scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-15308	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.

high[NEW] [high] CPython: Vulnerability allows Denial of Servicecert-bund
unknownVulnerability in CPython (July 10, 2026)cert-fr-avis

CVE-2026-15308: The incremental HTML parser (html.parser.HTMLParser) allows for CPU denial-of-service through repeated unterminated markup declarations when processing uncontrolled data.

Details

Exploitation outlook

Referenced CVEs

Same CVEs, other sources

More from NVD Recent CVEs