CVE-2019-20907 — In Lib/tarfile
In Lib/tarfile.py in Python through 3.8.3, an attacker is able to craft a TAR archive leading to an infinite loop when opened by tarfile.open, because _proc_pax lacks header validation.
Published
2020-07-13T13:15:10.763
Last modified
2026-10-14T08:17:01.633
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
01What is this vulnerability?
In Lib/tarfile.py in Python through 3.8.3, an attacker is able to craft a TAR archive leading to an infinite loop when opened by tarfile.open, because _proc_pax lacks header validation.
02Affected products
No structured affected-product list available — see references below for vendor advisories.
03Active exploitation status
Not currently listed on the CISA Known Exploited Vulnerabilities (KEV) catalog. EPSS is the best forward-looking signal — see the EPSS row above.
04Recommended remediation
- Patch to a fixed version listed in the vendor advisory (see references below).
- Mitigate with WAF rules, network egress filters, or feature flags where the patch is not yet available.
- Hunt historical logs for exploitation indicators — see Detection signatures below.
05Technical details
For the full vendor write-up, exploit chains, and reference implementations, see the references list in section 09.
06Detection signatures
Ask SARA in chat to draft a starting detection for this CVE in your stack of choice.
07Related CVEs
No directly-cited follow-up CVEs in the KB record for this advisory. The references list in section 09 carries the vendor cross-references.
08Timeline
- Published: 2020-07-13T13:15:10.763
- Last modified: 2026-10-14T08:17:01.633
09References
- lists.opensuse.org — http://lists.opensuse.org/opensuse-security-announce/2020-08/msg00051.html
- lists.opensuse.org — http://lists.opensuse.org/opensuse-security-announce/2020-08/msg00052.html
- lists.opensuse.org — http://lists.opensuse.org/opensuse-security-announce/2020-08/msg00053.html
- lists.opensuse.org — http://lists.opensuse.org/opensuse-security-announce/2020-08/msg00056.html
- bugs.python.org — https://bugs.python.org/issue39017
- github.com — https://github.com/python/cpython/pull/21454
- lists.debian.org — https://lists.debian.org/debian-lts-announce/2020/08/msg00034.html
- lists.debian.org — https://lists.debian.org/debian-lts-announce/2020/11/msg00032.html
- lists.debian.org — https://lists.debian.org/debian-lts-announce/2023/05/msg00024.html
- lists.fedoraproject.org — https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedorapro…
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