SEPTEMBER 19, 2026
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Case File

CVE-2026-77751

HIGH · CVSS 8.8 EPSS 0.48% Public Exploit

Source: NVD + CISA KEV + EPSS · Published 2026-08-21 · Last synced 2026-09-18

CyberRota Analysis

AI-Generated

A path traversal vulnerability in the handling of MISP object template names during STIX 2 import and export allows attackers to manipulate object names to escape the intended template directory, potentially accessing unauthorized files. This could lead to the disclosure of sensitive data or modification of object metadata, particularly if malicious object names are stored in MISP events and processed with elevated privileges later. Organizations using MISP should prioritize patching this vulnerability to safeguard their systems against potential exploitation.

Public Exploit Signal

A public exploit, PoC, GitHub repository or Metasploit reference was detected for this CVE.

Note: these links are listed for security research and verification purposes only.

CVE
CVE-2026-77751
Severity
HIGH
CVSS
8.8
EPSS
0.48%

Original NVD Description

A path traversal vulnerability existed in the handling of MISP object template names during STIX 2 import and MISP-to-STIX 2 export. MISP object names are passed to PyMISP's object-template resolution mechanism, which constructs a filesystem path by joining the configured MISP object-template directory, the object name, and definition.json. An object name originating from untrusted STIX or MISP content was not sufficiently restricted before being used in this filesystem path. An attacker able to supply a crafted object name containing path separators or traversal sequences such as ../ could therefore cause template resolution to escape the expected template directory and attempt to load a definition.json file from another location accessible to the process. During STIX 2 import, an attacker-controlled x_misp_name from a custom STIX object could directly reach this template-resolution mechanism. The issue could also become persistent. A malicious object name stored in a MISP event could later be processed again during STIX 2 export. Consequently, content originally introduced in one security context could trigger filesystem access later when the event is exported by a process operating with different or greater privileges. If a suitable definition.json file exists outside the intended template directory, its contents may be interpreted as a MISP object template and fields from that file copied into the converted object. This can result in unintended disclosure of locally accessible data represented by the template file and modification of the resulting object's metadata or semantics. The patches introduce strict validation of object-template names. Valid names are restricted to a single path component containing letters, digits, hyphens, or underscores. Names that do not meet these requirements are replaced with the generic unknown-template name before reaching PyMISP template resolution. The original rejected name is preserved in the object's comment and a warning is generated, preventing traversal while retaining the source information.