Security readout for executives and security teams
Plain-English summary
CVE-2021-27102 lets a low-privileged local attacker run operating-system commands on vulnerable Accellion FTA appliances. The vendor source states FTA 9_12_411 and earlier are affected, with FTA_9_12_416 and later fixed. Because CISA lists it in KEV, treat past or present vulnerable deployments as potentially targeted.
Executive priority
Prioritize within active vulnerability management because this is known exploited and can fully compromise affected systems. Business urgency is highest where Accellion FTA handled sensitive file transfers or remained on vulnerable versions after disclosure.
Technical view
This is CWE-78 OS command injection in Accellion FTA through a local web service call. CVSS 3.1 is 7.8 with local access, low complexity, low privileges, no user interaction, and high confidentiality, integrity, and availability impact. The public bundle does not provide exploit mechanics, indicators, or detailed compensating controls.
Likely exposure
Exposure is limited to organizations that deployed Accellion FTA 9_12_411 or earlier. The CVSS vector indicates exploitation requires local access and low privileges, not purely unauthenticated remote access. Confirm whether any FTA instance existed, including retired or isolated systems.
Exploitation context
Active exploitation is supported by CISA KEV listing for CVE-2021-27102. The provided sources do not identify attacker groups, exploitation volume, timelines, or technical indicators. Avoid assuming current compromise solely from version presence, but prioritize investigation where vulnerable FTA was used.
Researcher notes
Key uncertainty is evidence depth: the bundle confirms affected and fixed versions, CVSS, CWE, and KEV status, but not exploit details, indicators, or vendor mitigation beyond upgrading. Validation should focus on version evidence, asset history, and local access assumptions.
Mitigation direction
- Upgrade Accellion FTA to FTA_9_12_416 or later.
- Check Accellion guidance for product-specific remediation steps.
- Confirm unsupported or retired FTA systems are decommissioned.
- Review CISA KEV guidance and required remediation timelines.
- Preserve relevant logs before changing vulnerable systems.
Validation and detection
- Inventory all current and historical Accellion FTA deployments.
- Verify installed FTA version against 9_12_411 and FTA_9_12_416.
- Check whether vulnerable systems had local user access paths.
- Review logs for suspicious command execution or service activity.
- Document remediation status for vulnerability management tracking.
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-78: Command execution behavior lookup
Command injection weaknesses can lead defenders to review execution techniques and command interpreter 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-2021-27102 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
- 7.8 (3.1)
- Known Exploited
- Yes
- Published
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
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.
CISA KEV status
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:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H1.85.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
7.8HighVector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://www.accellion.com/products/fta/CVE reference · x_refsource_MISC
- https://github.com/accellion/CVEs/blob/main/CVE-2021-27102.txtCVE reference · x_refsource_MISC
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-27102CVE reference · government-resource
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 Neutralization of Special Elements used in an OS Command ('OS Command Injection')
Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.