Security readout for executives and security teams
Plain-English summary
SolarWinds Serv-U 15.3 had a directory traversal flaw that could let an unauthenticated remote party access files tied to the Serv-U installation and server. SolarWinds says the issue is resolved in Serv-U 15.3 Hotfix 1.
Executive priority
Treat this as a high-priority confidentiality issue for any Serv-U 15.3 deployment. The urgency is lower for environments without Serv-U 15.3, but asset verification is important because the issue is remotely reachable and unauthenticated by CVSS.
Technical view
CVE-2021-35250 is a CWE-22 directory traversal vulnerability in SolarWinds Serv-U 15.3 only. CVSS 3.1 is 7.5: network reachable, low complexity, no privileges, no user interaction, unchanged scope, high confidentiality impact, no integrity or availability impact.
Likely exposure
Exposure is most likely where SolarWinds Serv-U 15.3 is installed, especially if reachable over a network. The provided affected data lists version 15.3 only and marks the default status for other versions as unaffected.
Exploitation context
The CVSS vector supports unauthenticated network exploitation with low complexity. The provided bundle says KEV is false and includes no cited evidence of active exploitation, public exploit use, or exploitation in the wild.
Researcher notes
The source record does not provide exploit mechanics, affected file paths, or detailed detection indicators. Analysis should stay focused on version confirmation, hotfix verification, and evidence of unexpected file access related to Serv-U.
Mitigation direction
- Identify any SolarWinds Serv-U 15.3 installations.
- Apply Serv-U 15.3 Hotfix 1 where Serv-U 15.3 is present.
- Review SolarWinds advisory and hotfix guidance before operational rollout.
- Document unaffected systems that are not running Serv-U 15.3.
Validation and detection
- Confirm installed Serv-U version and hotfix level.
- Verify Serv-U 15.3 Hotfix 1 is installed on affected hosts.
- Review logs for unexpected access to Serv-U installation or server files.
- Track remediation status for every discovered Serv-U instance.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-22: File access and web shell behavior lookup
File traversal and upload weaknesses can lead teams to review file, web shell, execution, and collection telemetry. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2021-35250 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- High
- CVSS
- 7.5 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N3.93.6Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
7.5HighVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Source materials
- CVE List V5 sourceCVE List V5
- https://support.solarwinds.com/SuccessCenter/s/article/Serv-U-15-3-HotFix-1?language=en_USCVE reference · x_refsource_MISC
- https://www.solarwinds.com/trust-center/security-advisories/cve-2021-35250CVE reference · x_refsource_MISC
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.