CVE-2021-35211
CVE-2021-35211 is a critical-severity vulnerability in Solarwinds Serv-u with a CVSS 3.x base score of 9.0. It is listed in CISA's Known Exploited Vulnerabilities (KEV) catalog, confirming it has been exploited in the wild (added 2021-11-03). The underlying weakness is classified as CWE-787.
Key facts
- Severity: Critical (CVSS 3.x base score 9.0)
- CVSS v2: 10.0
- EPSS exploit prediction: 91% (100th percentile)
- Actively exploited: Yes — listed in CISA KEV (added 2021-11-03)
- EU (EUVD) id: EUVD-2021-21854
- EU exploitation: Flagged exploited in the ENISA EU Vulnerability Database (since 2021-11-03)
- Weakness: CWE-787
- Affected product: Solarwinds Serv-u
- Published:
- Last modified:
Description
Microsoft discovered a remote code execution (RCE) vulnerability in the SolarWinds Serv-U product utilizing a Remote Memory Escape Vulnerability. If exploited, a threat actor may be able to gain privileged access to the machine hosting Serv-U Only. SolarWinds Serv-U Managed File Transfer and Serv-U Secure FTP for Windows before 15.2.3 HF2 are affected by this vulnerability.
Frequently asked questions
- What is CVE-2021-35211?
- Microsoft discovered a remote code execution (RCE) vulnerability in the SolarWinds Serv-U product utilizing a Remote Memory Escape Vulnerability. If exploited, a threat actor may be able to gain privileged access to the machine hosting Serv-U Only. SolarWinds Serv-U Managed File Transfer and Serv-U Secure FTP for Windows before 15.2.3 HF2 are affected by this vulnerability.
- How severe is CVE-2021-35211?
- CVE-2021-35211 has a CVSS 3.x base score of 9.0, rated critical severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
- Is CVE-2021-35211 being actively exploited?
- Yes. CVE-2021-35211 is on CISA's Known Exploited Vulnerabilities (KEV) catalog, added on 2021-11-03, which means active exploitation has been confirmed. It should be prioritised for remediation.
- What products are affected by CVE-2021-35211?
- CVE-2021-35211 primarily affects Solarwinds Serv-u. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
- How do I fix CVE-2021-35211?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Because this CVE is known to be actively exploited, treat remediation as urgent — CISA KEV typically sets a short remediation deadline.
- Does CVE-2021-35211 have an EU (EUVD) identifier?
- Yes. CVE-2021-35211 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2021-21854. It is also flagged as exploited in the EUVD (since 2021-11-03).
- When was CVE-2021-35211 published?
- CVE-2021-35211 was published on 2021-07-14 and last updated on 2026-06-17.
References
- https://www.microsoft.com/security/blog/2021/07/13/microsoft-discovers-threat-actor-targeting-solarwinds-serv-u-software-with-0-day-exploit
- https://www.solarwinds.com/trust-center/security-advisories/cve-2021-35211
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-35211
Affected products (3)
- cpe:2.3:a:solarwinds:serv-u:*:*:*:*:*:*:*:*
- cpe:2.3:a:solarwinds:serv-u:15.2.3:-:*:*:*:*:*:*
- cpe:2.3:a:solarwinds:serv-u:15.2.3:hotfix1:*:*:*:*:*:*
More vulnerabilities in Solarwinds Serv-u
- CVE-2020-35481 — Critical (CVSS 9.8): SolarWinds Serv-U before 15.2.2 allows Unauthenticated Macro Injection.
- CVE-2026-28321 — Critical (CVSS 9.1): SolarWinds Serv-U is affected by a broken access control vulnerability that could allow arbitrary file read and write,…
- CVE-2026-28317 — Critical (CVSS 9.1): SolarWinds Serv-U is affected by an insecure direct object reference (IDOR) vulnerability that can lead to privilege…
- CVE-2026-28316 — Critical (CVSS 9.1): SolarWinds Serv-U is affected by an insecure direct object reference (IDOR) vulnerability that can lead to privilege…
- CVE-2026-28314 — Critical (CVSS 9.1): SolarWinds Serv-U is affected by an insecure direct object reference vulnerability that leads to an account takeover.…
- CVE-2026-28313 — Critical (CVSS 9.1): SolarWinds Serv-U is affected by an insecure direct object reference (IDOR) vulnerability that can lead to SMTP…
All CVEs affecting Solarwinds Serv-u →
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