CVE-2026-11972 PUBLISHED

tarfile opened in streaming mode mishandles EOF

Assigner: PSF
Reserved: 11.06.2026 Published: 23.06.2026 Updated: 24.06.2026

When using the "tarfile" module with a file opened in "streaming mode" (mode="r|") the tarfile module did not properly handle EOF, making archive parsing take exponentially longer.

Metrics

CVSS 4.0

CVSS Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
CVSS Score: 8.2

Exploitability Metrics		Vulnerable System Impact Metrics		Subsequent System Impact Metrics
Attack Vector	Network	Confidentiality	None	Confidentiality	None
Attack Complexity	Low	Integrity	None	Integrity	None
Attack Requirements	Present	Availability	High	Availability	None
Privileges Required	None
User Interaction	None

CVSS 4.0

Product Status

Vendor	Python Software Foundation
Product	CPython
Versions	Default: unaffected affected from 0 to 3.16.0 (excl.)

Credits

Ryan Hileman (https://github.com/lunixbochs) reporter
Petr Viktorin (https://github.com/encukou) coordinator
Stan Ulbrych (https://github.com/StanFromIreland) remediation reviewer

References

Problem Types

CWE-252 CWE
CWE-606 CWE
CWE-770 CWE