Multiple vulnerabilities in CPython (June 25, 2026)

unknownCVE-2026-11940 CVE-2026-0864 CVE-2026-11972

Multiple vulnerabilities have been discovered in CPython. Some of them allow an attacker to cause remote denial of service, a breach of data confidentiality, and a breach of data integrity.

CSIRTS triage

vendor: CPython product: CPython Denial of service Information disclosureOther

What: Multiple vulnerabilities can lead to remote denial of service and breaches of data confidentiality and integrity.
Who is affected: Users of CPython.
Urgency: Remediation is urgent due to the potential for denial of service and data breaches.
Action: Apply updates as they become available.

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

⚡ Watch CPython

Get an email when a new CPython advisory drops — max one per day, one-click unsubscribe.

Details

Source: CERT-FR Avis de sécurité (FR · national-cert · site)
Severity: unknown
Published: 2026-06-25
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-0800/

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-2026-119400.75% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 52% of all EPSS-scored CVEs.
Low exploitation riskCVE-2026-08640.13% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 3% of all EPSS-scored CVEs.
Low exploitation riskCVE-2026-119720.45% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 37% of all EPSS-scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-11940	coverage & exploitation status	NVD · CVE.org
CVE-2026-0864	coverage & exploitation status	NVD · CVE.org
CVE-2026-11972	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

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

high[UPDATE] [high] CPython: Multiple vulnerabilitiescert-bund
unknownCVE-2026-0864: Configuration Injection via Carriage Return (\r) in write() methodmsrc
unknownCVE-2026-11972: tarfile opened in streaming mode mishandles EOFmsrc