CVE Intelligence
Medium Access control

CVE-2026-9136 — Unauthorized ShadowAttribute modification in MISP via client-supplied identifier

A vulnerability was identified in the ShadowAttribute proposal creation workflow. The add action accepted user-controlled ShadowAttribute request data without removing the id field before saving the record. Because the underlying framework treats a supplied primary key as an instruction to update an existing record, an authenticated user able to submit shadow attribute proposals could provide the identifier of an existing ShadowAttribute and cause that record to be updated instead of creating a new proposal. This can result in unauthorized modification of existing shadow attributes, potentially affecting proposals associated with events the user should not be able to alter. Depending on deployment configuration and accessible API responses, the issue may also expose or move proposal data across event contexts. The vulnerability is caused by trusting a client-supplied primary key during object creation. The fix removes the id field from incoming ShadowAttribute data before processing, ensuring that the endpoint always creates a new proposal rather than updating an existing one. This has been fixed in MISP 2.5.38.

Published May 20, 2026 · Updated Oct 13, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: CIRCL

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.
How the score was calculated
  • EPSS 0.3% (30-day exploitation probability)+3
  • Technical severity (medium)+3

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation
Not confirmed
Not in CISA KEV — an absence of record, not proof it is unexploited.
EPSS FIRST
0.3%
ahead of 21% of scored CVEs · Oct 14, 2026
Affects
MISP
MISP and 1 more
CVSS base
6.5
Medium · 3 source(s)

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation
None
none · proof-of-concept · active
Automatable
No
can an attacker script the kill-chain steps
Technical impact
Partial
partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

  • Documented patch — github.com (NIST National Vulnerability Database)

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

  1. Identify exposed assets running the affected vendor/product/version combinations (MISP MISP, Misp-project Misp).
  2. Apply the fixed version or the patch documented under Remediation.
  3. Search available logs for exploit probes matching the vulnerability class (access control), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

VendorProductVersionsStatusSource
MISP MISP ≥ 2.5.0 and ≤ 2.5.37 Vulnerable CVE Program (cve.org) e CISA ADP
Misp-project Misp ≥ 2.5.0 and < 2.5.38 Vulnerable NIST National Vulnerability Database

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
None

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

ScoreVersionSeverityExpl.ImpactScored by
8.3 CVSS 4.0 High — — 5a6e4751-2f3f-4070-9419-94fb35b644e8 via NIST National Vulnerability Database
8.3 CVSS 4.0 High — — CIRCL via CVE Program (cve.org) e CISA ADP
6.5 CVSS 3.1 Medium 2.8 3.6 nvd@nist.gov via NIST National Vulnerability Database
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N (score shown at the top: nvd@nist.gov)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-639 · Authorization Bypass Through User-Controlled Key (IDOR)

Other CVEs with this weakness →

EPSS over time FIRST

Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 0.30%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

  • Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
  • Audit administrative actions and access to resources outside each user’s normal pattern.
web/proxy/WAF logsnetwork IDS/IPSauthentication logsapplication logs

Timeline

What happened to this CVE, newest first.

  • 2026
  • Affected products added · misp/misp
    Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
  • SSVC assessment updated
    Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
  • Record published
    Oct 13, 2026
  • Fix documented
    Oct 13, 2026 · NIST National Vulnerability Database
  • CVSS changed · 6.5
    Oct 13, 2026 · NIST National Vulnerability Database
  • Source status changed · → Analyzed
    Oct 13, 2026 · NIST National Vulnerability Database
  • Record created in this database
    Oct 13, 2026 · NIST National Vulnerability Database
  • CVE published
    May 20, 2026 · CIRCL

Source activity

Repeated readings are counted rather than listed.

  • 1× Official description updated · Oct 13, 2026 – Oct 13, 2026

References

1 on the record

Elsewhere on this site

MISP
every CVE for this vendor
Access control
same class
CWE-639
other pages naming this weakness

Related CVEs (same products)

  • CVE-2026-107278 MISP Object Sync Drops Objects and Attributes When Description Is Empty 8d
  • CVE-2026-107276 MISP Email OTP Race Condition Allows One-Time Password to Be Consumed by Multiple Concurrent Requests 8d
  • CVE-2026-107180 MISP: Forced TOTP Enrolment Bypassed via Non-Browser Request Types on otp_required Instances 8d
  • CVE-2026-107175 MISP Correlation Engine Fails to Refresh When Event Distribution or Sharing Group Changes 8d
  • CVE-2026-106513 MISP: Site-Admin Can Repoint Redis Workers to Attacker-Controlled Server via UI/API Configuration Change 9d
  • CVE-2026-104914 MISP: Soft-Deleted Attributes from Other Organizations Exposed via Attribute Search and Paginated View 13d

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-9136 is "Unauthorized ShadowAttribute modification in MISP via client-supplied identifier", rated Medium. It affects MISP (MISP); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 6.5 describes technical severity. EPSS 0.30% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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