Security readout for executives and security teams
Plain-English summary
NanaZip has a flaw in how it reads metadata from crafted .NET single-file application bundles. If a user processes a malicious bundle with an affected NanaZip version, the app can crash and may expose memory from the running process. The issue is fixed in NanaZip 6.0.1638.0 and 6.5.1638.0.
Executive priority
Treat as a normal-priority patch for endpoints or workflows using NanaZip with untrusted archives. Business impact is mainly application crash and possible process memory exposure, not confirmed system compromise.
Technical view
CVE-2026-27709 is a CWE-125 out-of-bounds read in NanaZip’s .NET Single File Application manifest parser. A malformed RelativePathLength can cause std::string construction beyond HeaderBuffer. Affected versions are 5.0.1252.0 to before 6.0.1638.0, and 6.1 to before 6.5.1638.0. CVSS v4.0 score is 5.1.
Likely exposure
Exposure is limited to systems where affected NanaZip versions parse untrusted or attacker-supplied .NET single-file bundles. The CVSS vector indicates local attack, low complexity, low privileges, and user interaction required.
Exploitation context
The source bundle does not report active exploitation, and the CVE is not marked as KEV. Practical abuse requires convincing or causing a user or workflow to open or inspect a crafted bundle with vulnerable NanaZip.
Researcher notes
Evidence is limited to the CVE record and GitHub advisory. The advisory describes malformed RelativePathLength causing an out-of-bounds read beyond HeaderBuffer. No public exploitation, workaround, or deeper root-cause details are provided in the source bundle.
Mitigation direction
- Upgrade NanaZip to 6.0.1638.0 or 6.5.1638.0 or later, as applicable.
- Avoid processing untrusted .NET single-file bundles with affected NanaZip versions.
- Check the vendor advisory for any updated guidance or release notes.
Validation and detection
- Inventory NanaZip installations and record exact versions.
- Flag versions 5.0.1252.0 through before 6.0.1638.0 as affected.
- Flag versions 6.1 through before 6.5.1638.0 as affected.
- Confirm upgraded endpoints report 6.0.1638.0, 6.5.1638.0, or later.
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-125: 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 lookupCVE-2026-27709 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
- Medium
- CVSS
- 5.1 (4.0)
- Known Exploited
- No
- Published
Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
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:4.0/AV:L/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N——Primary CVE scoreVulnerability scoring details
Base CVSS 4.0 score
5.1MediumVector: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/M2Team/NanaZip/security/advisories/GHSA-vr4w-xc78-w6fvCVE reference · x_refsource_CONFIRM
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.
Out-of-bounds Read
Out-of-bounds Read represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.