CVE-2021-20193: A flaw was found in the src/list.c of tar 1.33 and earlier.
Noroxi assessment
Priority: Monitor (action score 13/100)
- The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
- Probability of exploitation in the next 30 days: 1% (FIRST EPSS); higher than 65.3% of all records.
- Someone with local access to the system can trigger it. No account or password is required. A user must open a link or visit a page. No special conditions are required; it is repeatable.
- Fixed version: tar (Alpine:v3.10) 1.32-r1; tar (Alpine:v3.11) 1.32-r2; tar (Alpine:v3.13) 1.34-r0.
Low priority for now. Upgrade to tar (Alpine:v3.10) 1.32-r1; tar (Alpine:v3.11) 1.32-r2; tar (Alpine:v3.13) 1.34-r0 or later.
Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it
Primary sources: NVD · CVE.org · FIRST EPSS
A flaw was found in the src/list.c of tar 1.33 and earlier. This flaw allows an attacker who can submit a crafted input file to tar to cause uncontrolled consumption of memory. The highest threat from this vulnerability is to system availability.
- Published
- Mar 26, 2021
- Updated
- Oct 14, 2026
- EPSS
- 1.0% · 65th percentile
- CWE
- CWE-401
Report tools
Action score
13
Monitor
Low priority for now.
- CVSS
- 13 / 40 · 3.3 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 1.0%
CISA SSVC decision
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
Vulnrichment: CISA's decision-tree inputs.
Get told when this record changes
- Not in KEV: no record of exploitation in the wild
- No public exploit code on record
- A fix has been released
If any of these changes, we'll tell you in the daily email digest.
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Noroxi analysis
What does it mean in your environment?
The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.
We use this product, ask for helpAffected systems
Is your version affected?
Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.
| Vendor | Product | CPE |
|---|---|---|
| gnu | tar | cpe:2.3:a:gnu:tar |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- gnu tarup to 1.33 inclusive
Versions reported by the vendor
Affected version ranges reported by the assigning authority (redhat). Independent of NVD's CPE analysis and usually ahead of it.
n/a tar
- 1.33 and earlieraffected
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Alpine:v3.10 | tar | before 1.32-r1 | 1.32-r1 |
| Alpine:v3.11 | tar | before 1.32-r2 | 1.32-r2 |
| Alpine:v3.13 | tar | before 1.34-r0 | 1.34-r0 |
| Debian:12 | tar | before 1.34+dfsg-1 | 1.34+dfsg-1 |
| openSUSE:Leap 15.2 | tar | before 1.30-lp152.4.3.1 | 1.30-lp152.4.3.1 |
| openSUSE:Leap 15.3 | tar | before 1.34-150000.3.12.1 | 1.34-150000.3.12.1 |
| openSUSE:Tumbleweed | tar | before 1.34-5.1 | 1.34-5.1 |
| SUSE:Linux Enterprise Module for Basesystem 15 SP2 | tar | before 1.30-3.6.1 | 1.30-3.6.1 |
| SUSE:Linux Enterprise Module for Basesystem 15 SP3 | tar | before 1.34-150000.3.12.1 | 1.34-150000.3.12.1 |
| SUSE:Linux Enterprise Server 12 SP5 | tar | before 1.27.1-15.9.1 | 1.27.1-15.9.1 |
Same product
gnu: all recordsOther highest-scoring records for the same primary product.
- CVE-2005-2541Tar 1.15.1 does not properly warn the user when extracting setuid or setgid files, which may allow local users or remote attackers to gain p41Plan
- CVE-2016-6321Directory traversal vulnerability in the safer_name_suffix function in GNU tar 1.14 through 1.29 might allow remote attackers to bypass an i35Monitor
- CVE-2007-4476Buffer overflow in the safer_name_suffix function in GNU tar has unspecified attack vectors and impact, resulting in a "crashing stack."34Monitor
Published before and after this one in the same product
- ← EarlierCVE-2018-20482Dec 26, 2018 · GNU Tar through 1.30, when --sparse is used, mishandles file shrinkage during read access, which allows local users to cause a denial of ser18Monitor
- ← EarlierCVE-2019-9923Mar 22, 2019 · pax_decode_header in sparse.c in GNU Tar before 1.32 had a NULL pointer dereference when parsing certain archives that have malformed extend31Monitor
- Later →CVE-2022-48303Jan 30, 2023 · GNU Tar through 1.34 has a one-byte out-of-bounds read that results in use of uninitialized memory for a conditional jump.22Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| alpine:tar | 1.32-r1 · Alpine:v3.10 | Package registry (OSV) |
| debian:tar | 1.34+dfsg-1 · Debian:12 | Package registry (OSV) |
| opensuse:tar | 1.34-150000.3.12.1 · openSUSE:Leap 15.3 | Package registry (OSV) |
| suse:tar | 1.30-3.6.1 · SUSE:Linux Enterprise Module for Basesystem 15 SP2 | Package registry (OSV) |
| suse:tar | 1.34-150000.3.12.1 · SUSE:Linux Enterprise Module for Basesystem 15 SP3 | Package registry (OSV) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Someone with local access to the system can trigger it.
- No account or password is required.
- A user must open a link or visit a page.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- none
- Integrity
- none
- Availability
- low · the service can be disrupted
- Attack vector
- Local
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality impact
- None
- Integrity impact
- None
- Availability impact
- Low
Weakness class (CWE)
CWE-401 · Missing Release of Memory after Effective LifetimeCVSS vector
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L
nvd-primary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
MITRE has no CAPEC/ATT&CK mapping for this CWE.
Change log
- SSVC exploitation— → none
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
Show all references (4 more)Show less
Vendor advisories and official records. Exploit/PoC links are deliberately left out.