Security readout for executives and security teams
Plain-English summary
This flaw lets a low-privileged, authenticated user on affected FatPipe appliances promote themselves to administrator. That can turn a limited account into full control over a network connectivity platform. The supplied sources do not show active exploitation, but the impact is high because confidentiality, integrity, and availability are all affected.
Executive priority
Prioritize remediation where FatPipe systems protect business connectivity or VPN traffic. A compromised low-privilege account could become administrative control, creating material operational and data risk. No active exploitation is confirmed in the supplied sources, so urgency is high but not KEV-driven.
Technical view
CVE-2021-27855 is a missing-authorization privilege escalation in FatPipe WARP, IPVPN, and MPVPN before 10.1.2r60p91 and 10.2.2r42. A remote attacker with read-only credentials can gain administrative privileges. NVD-style scoring is CVSS 3.1 8.8, AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H, mapped to CWE-862.
Likely exposure
Exposure is most likely where FatPipe WARP, IPVPN, or MPVPN versions 10.1 or 10.2 are deployed below the fixed releases. The advisory also notes older FatPipe versions may be vulnerable. Exploitation requires valid read-only credentials and network reachability to the affected software.
Exploitation context
The bundle includes public researcher references, including a proof-of-concept file, but CISA KEV status is false and no supplied source confirms in-the-wild exploitation. Treat this as a credible privilege-escalation risk, not confirmed active exploitation.
Researcher notes
The key exposure condition is authenticated read-only access, not unauthenticated remote access. The affected boundary appears to be authorization enforcement, consistent with CWE-862. The public bundle does not provide enough evidence to assess exploit prevalence, default exposure, or compensating controls.
Mitigation direction
- Upgrade affected systems to 10.1.2r60p91 or 10.2.2r42.
- Check FatPipe FPSA001 guidance for older or uncertain versions.
- Review all read-only accounts for unexpected privilege changes.
- Restrict administrative access according to vendor guidance.
- Prioritize patching internet-reachable or broadly reachable management planes.
Validation and detection
- Inventory FatPipe WARP, IPVPN, and MPVPN deployments.
- Confirm running versions against 10.1.2r60p91 and 10.2.2r42.
- Identify read-only users with access to affected systems.
- Review logs for read-only users gaining administrative privileges.
- Document whether older versions are present and vendor-supported.
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-862: Authorization and privilege behavior lookup
Authorization weaknesses can support privilege escalation and valid-account review, depending on exploit path. 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 lookupPrivilege behavior lookup
The CVE wording references privilege impact, so privilege escalation and authorization behavior review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2021-27855 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
- 8.8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/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.
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:L/UI:N/S:U/C:H/I:H/A:H2.85.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
8.8HighVector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://www.zeroscience.mk/en/vulnerabilities/ZSL-2021-5685.phpCVE reference · x_refsource_MISC
- https://www.fatpipeinc.com/support/cve-list.phpCVE reference · x_refsource_CONFIRM
- https://www.zeroscience.mk/codes/fatpipe_privesc.txtCVE 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.