Security readout for executives and security teams
Plain-English summary
Rejetto HFS versions 3.0.0 through 3.2.0 can let an unauthenticated remote attacker forge an administrator login. If successful, the attacker can take full administrative control and potentially execute code through documented configuration functionality.
Executive priority
Treat as urgent for any exposed HFS server. The flaw can turn simple network reachability into administrator compromise and possible code execution, with no credentials required.
Technical view
The issue is predictable session-cookie signing. HFS uses Math.random() for the signing key and exposes related generator outputs in login responses. Sources say an attacker can reconstruct the generator state, recover the key, and forge an administrator session cookie.
Likely exposure
Exposure is most likely where Rejetto HFS 3.0.0 through 3.2.0 is deployed, especially if the service is reachable from the internet or untrusted networks.
Exploitation context
The provided sources support remote, unauthenticated, low-complexity exploitation and CVSS 9.8. They do not show CISA KEV listing or confirmed active exploitation.
Researcher notes
Evidence is strongest for the vulnerable design, affected range, patch release, and impact chain. The source bundle does not provide KEV status or confirmed in-the-wild exploitation.
Mitigation direction
- Upgrade Rejetto HFS to v3.2.1 per the release notes.
- Prioritize internet-facing HFS instances first.
- Restrict HFS access to trusted networks until patched.
- Review vendor and advisory updates for any additional guidance.
- Investigate unexpected administrator sessions or configuration changes.
Validation and detection
- Inventory all Rejetto HFS deployments and record versions.
- Flag versions 3.0.0 through 3.2.0 as affected.
- Confirm upgraded systems report v3.2.1 or later.
- Check whether HFS is reachable from untrusted networks.
- Review logs for unusual admin activity around login and configuration changes.
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-338: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. 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 lookupExecution behavior lookup
The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2026-61500 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
- No
- 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.
SSVC decision data
CVSS vector scores
2 official scoresWe 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:H3.95.9VulnCheckCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N——VulnCheckVulnerability scoring details
Base CVSS 4.0 score
9.3CriticalVector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
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
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- CVE publishedCVE Program
The CVE record was published.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
Source materials
- CVE List V5 sourceCVE List V5
- hfs v3.2.1 Release NotesCVE reference, VulnCheck · release-notes, patch
- https://www.vulncheck.com/advisories/rejetto-hfs-session-forgery-via-predictable-signing-keyCVE reference, VulnCheck · third-party-advisory
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.
Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG)
Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG) represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.