SonicWall NSM is widely deployed for network security; a critical Zip Slip (CVSS 9.1) enabling arbitrary file writes could disrupt infrastructure and lead to RCE or config compromise.
CVE-2026-81939
Zip Slip in SonicWall NSM On-Prem allows extracting files outside target directory.
Is CVE-2026-81939 being exploited?
Not confirmed. CVE-2026-81939 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.73% probability of exploitation in the next 30 days.
How severe is CVE-2026-81939?
CVE-2026-81939 is rated Critical with a CVSS score of 9.1. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-81939?
Yes. A fix has been recorded for CVE-2026-81939. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-81939 affect?
CVE-2026-81939 affects SonicWall Network Security Manager (NSM) On-Prem, NSM file upload/archive processing. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-81939?
Install vendor patch immediately; restrict/disable archive uploads or isolate NSM until patched.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Arbitrary file write via crafted archive during upload, enabling file overwrite, config tampering or potential RCE on NSM host.
Immediate action required
- affected4.3.0 and earlier versions
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.