CVE-2026-77761

Threat-intelligence corruption via retained parser state

Published Aug 21, 2026 · Updated Aug 21, 2026

Parser state isolation failure in MISP-STIX 2026.7.8 and earlier allows attackers to contaminate later MISP events via crafted STIX documents. Reused STIX 1 and STIX 2 parser instances fail to clear galaxies, references, passive DNS bookkeeping, titles, dates, and timestamps between conversions. Exploitation requires application-level parser reuse and controlled document ordering, enabling false associations and limited cross-scope disclosure without code execution or service interruption.

CVSS severityUnavailable
Unscored
EPSS probability0.37%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Parser state isolation failure in MISP-STIX 2026.7.8 and earlier allows attackers to contaminate later MISP events via crafted STIX documents. Reused STIX 1 and STIX 2 parser instances fail to clear galaxies, references, passive DNS bookkeeping, titles, dates, and timestamps between conversions. Exploitation requires application-level parser reuse and controlled document ordering, enabling false associations and limited cross-scope disclosure without code execution or service interruption.

The record

CVE
CVE-2026-77761
Published
Aug 21, 2026
Updated
Aug 21, 2026
Vendor
MISP
Product
MISP-STIX
Classifications
T1565.001
Attack vector
Unavailable
Privileges
Unavailable

Timeline

How it unfolded

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

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

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 vectorUnavailable in this record.
Required privilegesUnavailable in this record.

What is affected?

MISP · MISP-STIXversion=0 <=2026.7.8

Published CVSS scores

No CVSS assessment is available in this record.

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)
VectorUnavailable
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1565.001Stored Data Manipulation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo