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CVE.org (no NVD analysis yet)· CNA CIRCL

CVE-2026-103858: MISP Incomplete Thread Authorization Allows Unauthorized Read and Post Access to Discussions

MediumCVSS 5.3 · v4.0—No exploit Fix available

Noroxi assessment

Priority: Monitor (action score 21/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.21% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: MISP MISP 2.5.48.

Low priority for now. Upgrade to MISP MISP 2.5.48 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

MISP contains an incomplete authorization check in the discussion posting functionality. When a user submits a post to a thread or replies to an existing post, the application only verified whether the target thread was restricted to a single organization (org-only distribution). It did not enforce the full thread access control list, including sharing-group membership and event-level visibility. As a result, an authenticated user who is outside the relevant sharing group or who does not have visibility on the associated event could: - Read the thread title and the content of the quoted post - Submit a new post into the discussion thread This constitutes both an information disclosure (reading restricted thread and post content) and an integrity issue (injecting content into a thread the user is not authorized to participate in). Affected: <2.5.48

Published
Oct 1, 2026
Updated
Oct 1, 2026
EPSS
0.2% · 12th percentile

Report tools

JSON

Action score

21

Monitor

Low priority for now.

CVSS
21 / 40 · 5.3 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · CIRCL
5.3
NVD has not scored this yet; the score shown is the CNA’s.

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

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2026-103858

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (CIRCL). Independent of NVD's CPE analysis and usually ahead of it.

  • MISP MISP

    • unspecified and later · before 2.5.48affected · semver

Same product

misp: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-103655MISP TOTP Code Replay Allows Duplicate Authentication Within Validity Period
    37Monitor
  • CVE-2026-90961MISP LdapAuth and LinOTPAuth Authentication Bypass via Empty or Non-String Credentials
    37Monitor
  • CVE-2026-56422MISP Core: Mass Assignment and Object Re-ownership via Unvalidated Request Fields
    37Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2026-103662Oct 1, 2026 · MISP Reflected XSS in Taxonomy Tag Confirmation Forms
    20Monitor
  • ← EarlierCVE-2026-103664Oct 1, 2026 · MISP Reflected Cross-Site Scripting via Unsanitized Analyst Data Seed Parameter
    19Monitor
  • Later →CVE-2026-104900Oct 2, 2026 · MISP Stored XSS via Unescaped Count Field Value in Remote Event Preview Index
    21Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
MISP MISP2.5.48Vendor (CNA)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

  1. Published
  2. Fix recordedsame day
  3. TodayNov 13, 2026+43 d
EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2026-1036590 days apartMISP: Object Distribution ACL Bypass via Event Flattening Exposes Organisation-Only Attributes
    28Monitor
  • CVE-2026-1049081 days apartMISP Decaying Model Import Mass Assignment Allows Cross-Organization Model Overwrite and Default Flagging
    28Monitor
  • CVE-2026-8628325 days apartMISP UiBeta Collection View Bypasses Event ACL, Exposing Unauthorized Event Data
    28Monitor
  • CVE-2026-957549 days apartMISP: Disabled-user check ineffective in pre-authentication TOTP login branch
    27Monitor
  • CVE-2026-1049101 days apartMISP Information Disclosure via Related Events Listing Bypassing Per-Event Authorization
    21Monitor
  • CVE-2026-956719 days apartMISP Collections: Missing Authorization Check for Sharing Group on PUT Request in collections/add
    21Monitor

Not on record for this CVE: public bounty program.

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

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

Weakness class (CWE)

CWE-285 · Improper Authorization

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Change log

  1. SSVC exploitation— → none
  2. Exploit maturity— → none
  3. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records