CVE-2021-1871

Exploitation

Exploited in the wild. Listed in the CISA Known Exploited Vulnerabilities catalog on 2021-11-03. Federal remediation due 2021-11-17.

SSVC decision

• ExploitationactiveCISA reports credible evidence of active exploitation.
• 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

7.00% probability of exploitation activity in the next 30 days.

EPSS percentile

Ranks above 93.7% of scored records. A rank, not a probability.

NVD base score

9.8 (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:U/C:H/I:H/A:H

NVD analysis status

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

Red Hat severity

Moderate. Red Hat's rating for its own products, not a CVSS rating.

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

2021-04-02 18:06Z5 YR AGO

Last updated

2025-10-21 23:25Z10 MO AGO

Reserved

2020-12-08

Assigning CNA

apple

Record state

PUBLISHED

Severity

Critical (CVSS 9.8)

CNA CVSS vector

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

Weaknesses

• CWE-20Improper Input ValidationClass

Data version

5.1

Document digest

e3d9b7387fda44db63c8a282dc9173c655424dca7e76769c21761a979b034242

• support.apple.comhttps://support.apple.com/en-us/HT212147x_refsource_MISC
• support.apple.comhttps://support.apple.com/en-us/HT212146x_refsource_MISC
• lists.fedoraproject.orgFEDORA-2021-864dc37032https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/L3L6ZZOU5JS7E3RFYGLP7UFLXCG7TNLU/vendor-advisoryx_refsource_FEDORA
• www.debian.orgDSA-4923https://www.debian.org/security/2021/dsa-4923vendor-advisoryx_refsource_DEBIAN
• www.cisa.govhttps://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-1871government-resource