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01 Record

CVE-2021-20038

A Stack-based buffer overflow vulnerability in SMA100 Apache httpd server's mod_cgi module environment variables allows a remote unauthenticated attacker to potentially execute code as a 'nobody' user

CriticalKEVPUBLISHEDCNA: sonicwall
CNA base score9.8 CVSS v3.xCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
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02 Description

A Stack-based buffer overflow vulnerability in SMA100 Apache httpd server's mod_cgi module environment variables allows a remote unauthenticated attacker to potentially execute code as a 'nobody' user

03 Exploitation and scoring

Exploitation
Exploited in the wild. Listed in the CISA Known Exploited Vulnerabilities catalog on 2022-01-28. Federal remediation due 2022-02-11. Known ransomware campaign use: reported by CISA.
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
99.91% probability of exploitation activity in the next 30 days.
EPSS percentile
Equal to or higher than the score of 99.9% 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
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.

04 Metadata

Published
2021-12-08 09:55Z4 YR AGO
Last updated
2025-10-21 23:25Z1 YR AGO
Reserved
2020-12-17
Assigning CNA
sonicwall
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-121Stack-based Buffer OverflowVariant
  • CWE-787Out-of-bounds WriteBase
Data version
5.1
Document digest
d4899ee9d4e12e9438cc0f0bc696c8c8aff9f39b8e6c6879716b893e9ee0c2dc

05 Affected products

VendorProductVersionsPlatforms
SonicWallSonicWall SMA10010.2.0.8-37sv and earlier, 10.2.1.1-19sv and earlier, 10.2.1.2-24sv and earlier—

06 References