Security readout for executives and security teams
Plain-English summary
CVE-2021-33646 is a reported memory leak in libtar before 1.2.21. The available sources do not provide CVSS, active exploitation, or detailed impact. Business risk is mainly operational: systems that repeatedly process TAR archives could waste memory until vendor-updated packages are applied.
Executive priority
Handle through normal vulnerability management unless libtar processes untrusted archives in critical services. The evidence supports patching and exposure review, but not emergency response based on known exploitation.
Technical view
The issue is CWE-401 in libtar's th_read() path: allocated memory for t->th_buf.gnu_longname is not freed. Affected scope in the bundle is libtar versions before 1.2.21. Fedora, openEuler, and Debian LTS advisories indicate distribution-level updates exist, but the bundle does not describe exploitability details.
Likely exposure
Exposure is most likely where libtar is installed as an OS package or bundled in software that reads TAR archives. Prioritize servers, build systems, backup tools, and ingestion services that process user-supplied or high-volume archive files.
Exploitation context
The source bundle does not show CISA KEV listing or any cited active exploitation. It also does not provide a public exploit status. Treat exploitation as unconfirmed, with risk tied to memory pressure during archive processing.
Researcher notes
Evidence is limited to a memory leak description, affected libtar before 1.2.21, CWE-401, and distribution advisories. No CVSS vector, root-cause patch details, or exploitability assessment is included in the provided bundle.
Mitigation direction
- Inventory installed and bundled libtar versions.
- Update libtar to 1.2.21 or a vendor-fixed package.
- Apply relevant Fedora, openEuler, or Debian LTS advisories where applicable.
- Check vendor guidance for statically bundled libtar copies.
- Prioritize systems processing untrusted or high-volume TAR archives.
Validation and detection
- Confirm package version or vendor backport status.
- Review SBOMs and build manifests for bundled libtar.
- Identify services that parse TAR archives from external sources.
- Monitor archive-processing workloads for abnormal memory growth.
- Record compensating controls where updates are unavailable.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-401: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2021-33646 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Unknown
- CVSS
- Not scored
- Known Exploited
- No
- Published
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS and timeline data
No CVSS vectors or timeline events were available in the normalized CVE source material.
Source materials
- CVE List V5 sourceCVE List V5
- https://www.openeuler.org/en/security/safety-bulletin/detail.html?id=openEuler-SA-2022-1807CVE reference
- FEDORA-2022-fe1a4e3cf0CVE reference · vendor-advisory
- FEDORA-2022-50e8a1b51dCVE reference · vendor-advisory
- FEDORA-2022-44a20bba43CVE reference · vendor-advisory
- FEDORA-2022-88772d0a2dCVE reference · vendor-advisory
- FEDORA-2022-ccc68b06ccCVE reference · vendor-advisory
- https://lists.debian.org/debian-lts-announce/2025/01/msg00026.htmlCVE reference
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Missing Release of Memory after Effective Lifetime
Missing Release of Memory after Effective Lifetime represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.