CVE-2026-77751Network attack vector

File disclosure and metadata modification via template-name traversal

Published Aug 21, 2026 · Updated Aug 25, 2026

Path traversal in MISP-STIX 2026.7.8 and earlier allows remote attackers to disclose local file data through crafted object names. The converter passes an unvalidated STIX x_misp_name or stored MISP object name into PyMISP's template path join, escaping the template directory to load definition.json. A suitable file must exist at the traversed location; parsed fields can enter converted object metadata, exposing accessible content and changing object semantics.

CVSS severity8.8
High
EPSS probability0.48%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Path traversal in MISP-STIX 2026.7.8 and earlier allows remote attackers to disclose local file data through crafted object names. The converter passes an unvalidated STIX x_misp_name or stored MISP object name into PyMISP's template path join, escaping the template directory to load definition.json. A suitable file must exist at the traversed location; parsed fields can enter converted object metadata, exposing accessible content and changing object semantics.

The record

CVE
CVE-2026-77751
Published
Aug 21, 2026
Updated
Aug 25, 2026
Vendor
MISP
Product
MISP-STIX
Classifications
CWE-22, T1005
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 21, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 25, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <=2026.7.8

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

MISP · MISP-STIXversion=0 <=2026.7.8

Published CVSS scores

8.8CIRCLCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-22Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
T1005Data from Local System

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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