Exploitation evidence
Known exploited · CISA KEV listed
Added 2021-11-03. Ransomware campaign use: Known.
CISA required action: Apply updates per vendor instructions.
CISA due date: 2021-11-17. This is the catalog’s deadline, not an assessment of your organization’s exposure.
KEV checked 13 Nov 2026, 00:20 Jerusalem · Original catalog ↗Reported products and versions
SolarWinds / Serv-U Managed File Transfer Server and Serv-U Secured FTP
Default status: Not specified
- affected: SolarWinds Serv-U to < 15.2.3 HF1 (custom)
Fixes and workarounds
SolarWinds has released a hotfix 15.2.3 HF2 It is suggested to upgrade to the latest hotfix as soon as possible
Reported workarounds: SolarWinds advises to disconnect Serv-U Server from internet until patched.
Sources and related reporting
Observed change timeline
History begins when Egret first downloads each source. It is not the complete upstream CVE history.
12 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-12",
"epss": 0.9116,
"percentile": 0.99812
}10 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-10",
"epss": 0.9116,
"percentile": 0.99811
}09 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-09",
"epss": 0.9116,
"percentile": 0.9981
}08 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-08",
"epss": 0.9116,
"percentile": 0.9981
}07 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-07",
"epss": 0.9116,
"percentile": 0.99811
}06 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-06",
"epss": 0.9116,
"percentile": 0.99811
}06 Nov 2026, 06:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-05",
"epss": 0.9116,
"percentile": 0.9981
}05 Nov 2026, 12:20 Jerusalem · CVE Program record changed
Stored CNA snapshot at this observation.
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}04 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-04",
"epss": 0.9116,
"percentile": 0.9981
}03 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-03",
"epss": 0.9116,
"percentile": 0.99809
}03 Nov 2026, 02:22 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-02",
"epss": 0.9116,
"percentile": 0.99809
}03 Nov 2026, 02:22 Jerusalem · CISA KEV status changed
Stored KEV snapshot at this observation.
{
"cveID": "CVE-2021-35211",
"cwes": [
"CWE-787"
],
"dateAdded": "2021-11-03",
"dueDate": "2021-11-17",
"forensicTriage": "No",
"knownRansomwareCampaignUse": "Known",
"notes": "https://nvd.nist.gov/vuln/detail/CVE-2021-35211",
"product": "Serv-U",
"requiredAction": "Apply updates per vendor instructions.",
"shortDescription": "SolarWinds Serv-U contains an unspecified memory escape vulnerability which can allow for remote code execution.",
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"vulnerabilityName": "SolarWinds Serv-U Remote Code Execution Vulnerability"
}