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CVE-2021-29136

20
FAUCET Score

CVE-2021-29136 describes a symlink traversal vulnerability in Open Container Initiative umoci versions prior to 0.4.7, affecting Linux Foundation and Sylabs Singularity and umoci products. An attacker can craft a malicious image that, when unpacked using "umoci unpack" or "umoci raw unpack," allows them to overwrite arbitrary host paths. Rated as Medium severity (CVSS 5.5), this local attack requires low privileges and user interaction is not required, but it only impacts integrity (I:H) with no confidentiality or availability impact. There is no evidence of active exploitation, publicly available exploit code, or significant community discussion or media coverage surrounding this vulnerability.

Impacted Technologies

VendorProductVersion(s)CPE
< 0.4.7CPE matchmatch criteria
cpe:2.3:a:linuxfoundation:umoci:*:*:*:*:*:*:*:*
< 3.7.3CPE matchmatch criteria
cpe:2.3:a:sylabs:singularity:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

5.5MEDIUM

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N

Attack Vector
LOCAL
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
HIGH
Availability Impact
NONE
Exploitability Score
1.8
Impact Score
3.6
CvssVersion
3.1

Exploit Intelligence

EPSS Score
0.34%
Probability of exploitation in next 30 days
EPSS Percentile
26.9%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0034 is in the 83rd percentile among its peer group of 15,938 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.0 Bluesky, 0.0 Mastodon, and 0.1 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (2)

github_advisorypatch availablevia nvd_reference
View patch
gopatch availablevia ghsa
Product: github.com/opencontainers/umociFixed in: 0.4.7

Vendor Advisories (1)

goGHSA-9m95-8hx6-7p9vmedium

Improper input validation in umoci

Feb 15, 2022

References

github.com / opencontainers/umoci/commit/d9efc31daf2206f7d3fdb839863cf7a576a2eb57
PatchThird Party Advisory
github.com / opencontainers/umoci/security/advisories/GHSA-9m95-8hx6-7p9v
Third Party Advisory
openwall.com / lists/oss-security/2021/04/06/2
Mailing ListPatchThird Party Advisory