Critical · CVSS 9.3CVE-2026-61500

Rejetto HFS < 3.2.1 Session Forgery via Predictable Signing Key

Answer in brief

CVE-2026-61500 records a Critical severity (CVSS 9.3) vulnerability in Rejetto HFS < 3.2.1 Session Forgery via Predictable Signing Key. The current sources do not mark it as known exploited. The current feed maps rejetto/hfs (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Jul 13, 2026Updated Oct 1, 2026Source checked Oct 1, 2026First seen by HOL Jul 13, 2026Material review Oct 1, 2026

Upstream Advisory

Key facts

Risk: Critical · CVSS 9.3
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Not reported

Why this deserves its current priority

CVSS is 9.3. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps rejetto/hfs (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
rejetto/hfsgeneric	*	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for rejetto/hfs.
Review the reported fix. Monitor this advisory for an available fix and review any installs of the affected package.

Evidence timeline and material changes

Published upstream
Jul 13, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Oct 1, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Jul 13, 2026

Sources and claim methodology

Upstream source description

Rejetto HFS 3.0.0 through 3.2.0 derives its session-cookie signing key from the non-cryptographic Math.random() generator and discloses outputs of the same generator to unauthenticated clients during login. A remote attacker can collect a small number of login responses, reconstruct the generator's state, recover the signing key, and forge a valid administrator session cookie, leading to full administrative access and remote code execution via the server_code configuration feature.

Quoted source text, attributed separately from HOL analysis.