Page generated: 08 Nov 2026, 06:20 UTC
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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 in the appliance. This vulnerability affected SMA 200, 210, 400, 410 and 500v a…

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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 in the appliance. This vulnerability affected SMA 200, 210, 400, 410 and 500v appliances firmware 10.2.0.8-37sv, 10.2.1.1-19sv, 10.2.1.2-24sv and earlier versions.
CVSS 9.8 (CRITICAL) KEV: KNOWN CATALOG

Attention and evidence

HYPE SCORE
0.0/10
REALITY · THREAT PRIORITY
9.0/10
General review priority; not probability

Evidence confidence: Exploitation recorded

Why this priority?
  • Recorded exploitation baseline: +7.00
  • Technical severity: CVSS 9.8: +1.47
  • Fresh EPSS: 99.91%: +0.50

General review priority, not probability, victim count or asset-specific risk. A range covers missing CVSS/EPSS inputs within the current evidence state.

Sources: 10 documents and public datasets.

Hype components

Headline sample (25%)
0/100
Press, 30 days (60%)
0/100
Grounded branding (15%)
0/100
HYPE TOTAL0/100

Sources and documents

Halcyon.AI
Press · 27 Jul 2026, 07:00 · World Leaks - Halcyon.AI
SecurityWeek
Press · 24 Sep 2025, 07:00 · SonicWall Updates SMA 100 Appliances to Remove Overstep Malware - SecurityWeek
BleepingComputer
Press · 24 Jul 2025, 07:00 · SonicWall urges admins to patch critical RCE flaw in SMA 100 devices - BleepingComputer
The Hacker News
Press · 16 Jul 2025, 07:00 · UNC6148 Backdoors Fully-Patched SonicWall SMA 100 Series Devices with OVERSTEP Rootkit - The Hacker News
The Record from Recorded Future News
Press · 16 Jul 2025, 07:00 · Google spots tailored backdoor malware aimed at SonicWall appliances - The Record from Recorded Future News
See all 10 source documents
SecurityWeek
Press · 16 Jul 2025, 07:00 · SonicWall SMA Appliances Targeted With New ‘Overstep’ Malware - SecurityWeek
Google Cloud
Press · 16 Jul 2025, 07:00 · Ongoing SonicWall Secure Mobile Access (SMA) Exploitation Campaign using the OVERSTEP Backdoor - Google Cloud
CyberScoop
Press · 16 Jul 2025, 07:00 · SonicWall customers hit by fresh, ongoing attacks targeting fully patched SMA 100 devices - CyberScoop
The Record from Recorded Future News
Press · 09 Feb 2023, 08:00 · US and South Korea accuse North Korea of using hospital ransoms to fund more hacking - The Record from Recorded Future News
TechTarget
Press · 11 Jan 2022, 08:00 · SonicWall SMA 100 appliances beset by multiple vulnerabilities - TechTarget

Score evolution

● Hype   ● Reality

Earlier evidence-support scores are retained in history; this chart shows only the current priority definition.

First record: hype 0.0 · reality 9.0 (2026-11-02 15:12). The curve appears once the score changes.

Public exploit evidence

0

Public exploit entries / repo candidates

Evidence context and dated references

Reality is general threat/review priority, combining observed exploitation, CVSS severity and fresh EPSS. Evidence confidence is separate. This is not calibrated risk, a victim count or an asset-specific assessment. A range reflects missing numeric inputs.

Evidence in context

Confidence in exploitation evidence
Exploitation recorded
Priority basis
Recorded exploitation; CVSS 9.8; EPSS 99.9%
Attention, last 30 days
0 distinct story titles; 0 press documents; 0 publisher domains.
Technical potential
network access, no prior privileges, no user interaction.
Observed activity
Exploitation recorded in CISA KEV.
Known scale
Not quantified.
Evidence confidence basis
Trusted exploitation confirmation

Score evaluated: 2026-11-05 13:58:22.744333+00:00 · EPSS snapshot: 2026-11-05T12:03:04Z

Source event timeline
Published
08 Dec 2021, 09:55
First press mention
11 Jan 2022, 08:00
Added to the CISA KEV catalog
28 Jan 2022, 00:00
Latest press mention
27 Jul 2026, 07:00
Score calculated
05 Nov 2026, 13:58