What’s Vulnerable › Vulnerabilities

CVE-2021-29136

• Severity: medium (CVSS 5.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-04-06 · updated 2026-06-17
• Weakness: CWE-20

Description

Open Container Initiative umoci before 0.4.7 allows attackers to overwrite arbitrary host paths via a crafted image that causes symlink traversal when "umoci unpack" or "umoci raw unpack" is used.

Affected products

• Linuxfoundation Umoci: before 0.4.7 — fixed in 0.4.7
• sylabs singularity: before 3.7.3 — fixed in 3.7.3

How to fix

Upgrade to a fixed version: Linuxfoundation Umoci 0.4.7; sylabs singularity 3.7.3. Check the vendor advisory for mitigations.

References

• http://www.openwall.com/lists/oss-security/2021/04/06/2
• https://github.com/opencontainers/umoci/commit/d9efc31daf2206f7d3fdb839863cf7a576a2eb57
• https://github.com/opencontainers/umoci/security/advisories/GHSA-9m95-8hx6-7p9v
• http://www.openwall.com/lists/oss-security/2021/04/06/2
• https://github.com/opencontainers/umoci/commit/d9efc31daf2206f7d3fdb839863cf7a576a2eb57
• https://github.com/opencontainers/umoci/security/advisories/GHSA-9m95-8hx6-7p9v

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