CVE-2021-33643
Critical · CVSS 9.1libtar — Out-of-bounds read via malloc(0) on crafted tar header
- CVSS
- 9.1
- nvd
- EPSS
- 1.45%
- 70th pct
- KEV
- No
- Class
- oss containerizable
- CWE-125, CWE-125
Description
An attacker who submits a crafted tar file with size in header struct being 0 may be able to trigger an calling of malloc(0) for a variable gnu_longlink, causing an out-of-bounds read.
Search profile — drives PoC discovery
Symbols gnu_longlinkmalloc(0)th_get_sizegnu_longnametar_headerTH_ISREGget_longlink_size
Keywords CVE-2021-33643libtarout-of-bounds readgnu_longlinkmalloc zerotar header size 0crafted tar fileCWE-125
Versions: libtar <= 1.2.20
Ranked PoCs (1) — best first
Heuristic ranking — not yet expert-vetted. Scored on structure + provenance, not execution.
- ★ 0em1ga3l/cve-publicationdate-extractor needs reviewtrickest
Recall-favoring discovery; ranking by the Stage-4 scorer (Adam's rubric). Scanner/aggregator repos are hidden.
References
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/4S4PJRCJLEAWN2EKXGLSOBTL7O57V7NC/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/5YSHZY753R7XW6CIKJVAWI373WW3YRRJ/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/7Q26QDNOJDOFYWMJWEIK5XR62M2FF6IJ/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/7WX5YE66CT7Y5C2HTHXSFDKQWYWYWJ2T/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/OD4HEBSTI22FNYKOKK7W3X6ZQE6FV3XC/
- https://www.openeuler.org/en/security/safety-bulletin/detail.html?id=openEuler-SA-2022-1807
- https://lists.debian.org/debian-lts-announce/2025/01/msg00026.html
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/4S4PJRCJLEAWN2EKXGLSOBTL7O57V7NC/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/5YSHZY753R7XW6CIKJVAWI373WW3YRRJ/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/7Q26QDNOJDOFYWMJWEIK5XR62M2FF6IJ/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/7WX5YE66CT7Y5C2HTHXSFDKQWYWYWJ2T/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/OD4HEBSTI22FNYKOKK7W3X6ZQE6FV3XC/
Status: enriched · ingested 2026-06-23T18:00:15.000Z · profiled 2026-06-24T06:30:26.000Z