CVE-2021-41556

Exploitation

Public exploit code exists. CISA's assessment records a public proof of concept. That is not a report of exploitation in the wild.

SSVC decision

• ExploitationpocPublic proof-of-concept exploit code exists. Not a report of exploitation in the wild.
• AutomatableyesAn attacker can reliably automate reconnaissance through exploitation, so this scales.
• Technical ImpacttotalSuccessful exploitation gives total control of the vulnerable component.

CISA publishes the decision points, not a final SSVC decision. The decision also depends on mission and well-being impact, which is a property of your deployment rather than of the vulnerability.

EPSS probability

2.91% probability of exploitation activity in the next 30 days.

EPSS percentile

Equal to or higher than the score of 86.9% of scored records. A rank, not a probability.

NVD base score

10.0 (CVSS v3.x), scored by the NVD independently of the CNA.

NVD CVSS vector

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

NVD analysis status

Modified. NVD last modified this record on 2026-06-17.

Red Hat severity

No Red Hat rating. Red Hat rates the CVEs that affect its products.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

Published

2022-07-28 20:41Z4 YR AGO

Last updated

2026-05-29 18:48Z5 MO AGO

Reserved

2021-09-22

Assigning CNA

mitre

Record state

PUBLISHED

Severity

Critical (CVSS 10.0)

CNA CVSS vector

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

Weaknesses

• CWE-125Out-of-bounds ReadBase

Data version

5.2

Document digest

33f7ec8e824adf3a29aaf2fe66a46bb64e47230fa6cc9e90472c28076d2368ab

• github.comhttps://github.com/albertodemichelis/squirrel/commit/23a0620658714b996d20da3d4dd1a0dcf9b0bd98x_refsource_MISC
• www.squirrel-lang.orghttp://www.squirrel-lang.org/#downloadx_refsource_MISC
• blog.sonarsource.comhttps://blog.sonarsource.com/squirrel-vm-sandbox-escape/x_refsource_MISC
• lists.fedoraproject.orgFEDORA-2022-e81c0db364https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BV7SJJ44AGAX4ILIVPREIXPJ2GOG3FKV/vendor-advisoryx_refsource_FEDORA
• lists.fedoraproject.orgFEDORA-2022-e139f256f6https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/M3FQILX7UUEERSDPMZP3MKGTMY2E7ESU/vendor-advisoryx_refsource_FEDORA
• www.sonarsource.comhttps://www.sonarsource.com/blog/squirrel-vm-sandbox-escape/exploit