Vulnerability in CPython (July 10, 2026)

CSIRTS triage

What

A vulnerability allows an attacker to cause remote denial of service.

Who is affected

Deployments of CPython are affected.

Urgency

Remediation is urgent due to the potential for remote denial of service.

Action

Update to the latest version of CPython.

AI-assisted analysis generated from the source advisory — verify against the original.

Details

Source

CERT-FR Avis de sécurité (FR · national-cert · site)

Severity

unknown

Published

2026-07-10

Exploitation

Not in CISA KEV at last sync

Language

Machine-translated to English — verify against the original

Original advisory: https://www.cert.ssi.gouv.fr/avis/CERTFR-2026-AVI-0858/

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

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
• highCVE-2026-15308: The incremental HTML parser (html.parser.HTMLParser) allows for CPU denial-of-service through …nvd

Recent advisories for CPython

A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.

• high[NEW] [high] CPython: Vulnerability allows Denial of Servicecert-bund · 2026-07-10
• low[UPDATE] [low] CPython: Vulnerability allows file manipulationcert-bund · 2026-07-10
• medium[UPDATE] [medium] CPython: Vulnerability allows bypassing security measurescert-bund · 2026-07-10
• medium[UPDATE] [medium] Cpython: Multiple vulnerabilitiescert-bund · 2026-07-10
• low[UPDATE] [low] CPython: Vulnerability allows unspecified attackcert-bund · 2026-07-10
• medium[UPDATE] [medium] cPython: Vulnerability allows Denial of Servicecert-bund · 2026-07-10

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