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NVD / CVE Program· CNA CIRCL

CVE-2026-91857: MISP: State-changing actions accessible via GET request enabling CSRF

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. No account or password is required. No special conditions are required; it is repeatable.
  • Fixed version: MISP MISP 2.5.46.

Low priority for now. Upgrade to MISP MISP 2.5.46 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

Affected versions of MISP expose several state-changing controller actions without restricting them to POST. The affected actions are:  - EventReportsController::purgeUnusedPictures()  - NoticelistsController::enableNoticelist()  - ServersController::removeOrphanedCorrelations()  - WorkflowsController::rebuildRedis() The patch adds allowMethod(['post']) to each action, preventing them from being triggered through ordinary GET requests. For purgeUnusedPictures(), the corresponding UI previously used $.get(). The fix converts that request to POST and supplies X-CSRF-Token, while the controller enables header-only CSRF validation for that AJAX action. Because GET requests can be induced cross-origin through links, images, redirects, or navigation, accepting GET for these state-changing operations can let an attacker trigger them using the authenticated victim's session. Version affected: ≤2.5.45

MediumCVSS 5.3 · v4.0—No exploit Fix available
Published
Sep 15, 2026
Updated
Sep 16, 2026
EPSS
0.2% · 11th 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:N/UI:P/VC:N/VI:L/VA:L/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-2026-91857

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

    • before 2.5.46affected · 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-2026-91846Sep 15, 2026 · MISP Collection Element Add Missing Authorization on Referenced Object UUID
    28Monitor
  • ← EarlierCVE-2026-91851Sep 15, 2026 · MISP Dashboard Template ACL Bypass Due to VARCHAR-to-Integer Type Coercion in Permission Flag Comparison
    21Monitor
  • Later →CVE-2026-91859Sep 15, 2026 · MISP Access Log Entry Overwritten by Error Controller's Second beforeFilter Pass
    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 MISP2.5.46Vendor (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.

No dated events beyond publication.

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-2026-8554611 days apartMISP Sharing Group Quick-Edit Actions Allow CSRF via State-Changing GET Requests
    34Monitor
  • CVE-2026-944046 days apartMISP CSRF vulnerability allows unauthorized attribute modification
    28Monitor
  • CVE-2026-5435995 days apartMISP automation endpoints may be exposed to CSRF when Sec-Fetch-Site protection is disabled by default
    28Monitor
  • CVE-2026-956587 days apartMISP CSRF vulnerability in workflow moduleStatelessExecution allows cross-site execution of workflow modules
    27Monitor
  • CVE-2026-8554711 days apartCross-Site Request Forgery via Attacker-Controlled REST Detection in MISP
    24Monitor
  • CVE-2026-908931 days apartMISP UserSettingsController CSRF Protection Bypass on setTheme, setHomePage, and eventIndexColumnToggle Endpoints
    20Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No special conditions are required; it is repeatable.

If successful

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

Weakness class (CWE)

CWE-352 · Cross-Site Request Forgery (CSRF)

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:L/VA:L/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

Root cause

State-changing requests rely on the session cookie the browser sends automatically; nothing verifies that the request came from the user’s own page.

The bug in code

The whole CWE-352 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

ts
app.use(session({ cookie: { httpOnly: true } }));app.post("/account/address", updateAddress);

Fixed

ts
app.use(session({ cookie: { httpOnly: true, sameSite: "lax" } }));app.post("/account/address", csrfProtection, updateAddress);

Attack context

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

ATT&CK techniques

—

Change log

  1. 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