Mandiant FLARE floss: Deserialization of untrusted data allows code execution
Summary
Mandiant FLARE floss before 3.2.0 deserializes untrusted Python Pickle data from Vivisect workspace files. A crafted cached workspace (<sample>.viv or .exe.viv) or a crafted .viv file can execute arbitrary code when an analyst runs floss on it. Exploitation requires that the victim is lured into analysing a malicious sample or workspace locally; the flaw is not remotely exploitable.
Affected
- Mandiant FLARE floss before 3.2.0 (CVE record)
- Release notes list v3.1.1 and earlier and the QUANTUMSTRAND pre-releases as affected; treat all versions before 3.2.0 as affected
Fixed in
- Upgrade to floss 3.2.0 or later (released 16 Oct 2026)
- Version 3.2.0 parses samples only as PE or ELF and loads an existing .viv workspace only if FLOSS_LOAD_VIV_WORKSPACE=1 is set
Workaround
- No vendor workaround known; upgrading is the fix
- Keep FLOSS_LOAD_VIV_WORKSPACE unset (documented default: disabled)
- Do not analyse .viv files or samples stored next to unknown .viv files
Exploitation
- No known exploitation found; CISA SSVC: exploitation none, not automatable
- No public proof of concept found at the time of research
- CVSS 4.0 score 8.7 (AV:L/AC:H/AT:P/PR:N/UI:A); NVD analysis pending
Our recommendation
- Update analyst workstations and analysis VMs to floss 3.2.0 or later
- Analyse malware only in isolated VMs
- Delete old or untrusted .viv workspace files
- Check whether your team or MSSP uses floss; no action needed if it is not used
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- MNDT-2026-0036 Mandiant advisory github.com
- floss 3.2.0 release github.com
- floss releases github.com
- floss usage documentation github.com
- CVE-2026-114198 on threatint cve.threatint.com
- CVE-2026-114198 on Strix www.strix.ai
- CVE-2026-114198 on HOL Guard hol.org
- CVE-2026-114198 on OpenCVE app.opencve.io
Researched and written up in English and German by an AI (Claude by Anthropic) based on NVD, CISA, EPSS and the sources listed. The vendor information is authoritative. Researched on 1 Nov 2026, 01:05.
Original description (NVD)
Deserialization of untrusted data in Mandiant FLARE floss releases before 3.2.0 allows arbitrary code execution when a crafted .viv or .exe.viv workspace is passed to the floss utility
Sources
The tracker combines official, freely usable data sources – updated continuously:
- NVD (NIST) – CVEs, rating (CVSS), affected products
- CISA KEV – vulnerabilities confirmed by CISA as actively exploited
- CISA Vulnrichment – CISA assessment (SSVC) in the official CVE record
- FIRST EPSS – probability of exploitation
- Microsoft MSRC – Patch Tuesday: vulnerabilities, severity, updates
- PoC-in-GitHub – public proof-of-concept repositories
- Metasploit (Rapid7) – modules of the Metasploit Framework
- Exploit-DB (OffSec) – archive of public exploits (links only)
- Patch days: official vendor pages (linked per vendor) (Vendor patch days)
This product uses data from the NVD API but is not endorsed or certified by the NVD. EPSS data © FIRST.org.
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