Security readout for executives and security teams
Plain-English summary
CVE-2021-27103 is a critical vulnerability in Accellion FTA that could let an unauthenticated remote attacker abuse the server to make unintended requests. Because CISA lists it as known exploited and the CVSS impact is high for confidentiality, integrity, and availability, exposed legacy FTA systems require urgent attention.
Executive priority
Treat this as urgent if Accellion FTA exists in the environment. CISA KEV status means exploitation has been observed, and the vulnerability affects a file transfer appliance that may handle sensitive business data.
Technical view
Accellion FTA 9_12_411 and earlier is affected by server-side request forgery through a crafted POST request to wmProgressstat.html. The source bundle identifies CWE-918 and CVSS 3.1 score 9.8. The fixed version is FTA_9_12_416 and later.
Likely exposure
Organizations are exposed if they still operate Accellion FTA versions 9_12_411 or earlier, especially if reachable from the internet or untrusted networks. The affected product fields in the bundle are incomplete, so version inventory is the key exposure check.
Exploitation context
Active exploitation is supported by the CISA Known Exploited Vulnerabilities listing. The provided sources do not include exploit mechanics, indicators of compromise, or attacker tooling details, so validation should focus on asset/version status and vendor-provided guidance.
Researcher notes
The bundle has incomplete structured affected-product metadata, but the narrative description clearly identifies Accellion FTA 9_12_411 and earlier. No source-provided exploit steps or IOC detail were included, so avoid assumptions beyond SSRF, fixed version, and KEV status.
Mitigation direction
- Upgrade Accellion FTA to FTA_9_12_416 or later.
- Identify and prioritize any internet-facing FTA systems.
- Follow Accellion guidance for any additional remediation or investigation steps.
- Restrict access to affected FTA systems until patch status is verified.
Validation and detection
- Inventory Accellion FTA deployments and record exact versions.
- Confirm no production FTA system is running 9_12_411 or earlier.
- Review available logs for suspicious wmProgressstat.html activity without replaying traffic.
- Check CISA KEV and Accellion references for current remediation guidance.
Public sources used
Michael Williams reviewed this cited source version on .
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-918: Information exposure and cloud metadata lookup
Information exposure and SSRF weaknesses can make discovery, cloud metadata, and credential material review relevant. 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 lookupCloud metadata behavior lookup
The CVE wording references SSRF or metadata access, so cloud discovery and credential material review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2021-27103 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
- Critical
- CVSS
- 9.8 (3.1)
- Known Exploited
- Yes
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/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:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H3.95.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
9.8CriticalVector: CVSS:3.1/AV:N/AC:L/PR:N/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-2021-27103.txtCVE reference · x_refsource_MISC
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-27103CVE 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.
Server-Side Request Forgery (SSRF)
Server-Side Request Forgery (SSRF) represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.