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NVD / CVE Program· CNA CIRCL

CVE-2026-86452: MISP Unauthenticated Mail Endpoints Allow Unbounded Storage Consumption and Request Flooding

Noroxi assessment

Priority: Monitor (action score 34/100)

  • 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: 0.54% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • According to CISA the attack is automatable: targets can be found by mass scanning.
  • No fixed version is recorded, but the references include a patch (commit or PR) link.

Low priority for now. See the fix and affected versions sections below.

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 permit unauthenticated or weakly constrained request paths to perform persistent work without adequate input bounds or rate limiting. The users/forgot password-reset endpoint accepted an attacker-controlled email value without first imposing a reasonable length bound or validating its format. That value was then used to create an audit log entry and queue a password-reset job, causing the supplied value to be persisted more than once per request. The commit explicitly states that an unbounded unauthenticated request field was stored twice per call with no throttle. The fix adds:  - a maximum email input length of 1024 bytes;  - email-format validation before persistent work;  - a per-source pre-authentication request budget;  - HTTP 429 responses when that budget is exceeded;  - a 15-minute cooldown for API-access request emails;  - POST-only handling and CSRF protection for the API-access request endpoint. The new flood filter is specifically intended to limit persistent storage costs from anonymous requests such as password resets, registrations, and failed REST authentication attempts. Version affected: ≤2.5.45

HighCVSS 8.7 · v4.0—No exploit No fix recorded
Published
Sep 7, 2026
Updated
Sep 14, 2026
EPSS
0.5% · 45th percentile

Report tools

JSON

Action score

34

Monitor

Low priority for now.

CVSS
34 / 40 · 8.7 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.5%

CISA SSVC decision

Exploitation
none
Automatable
yes
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · CIRCL
8.7
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:N/VC:N/VI:N/VA:H/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
  • No fixed version yet

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

Follow CVE-2026-86452

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.

VendorProduct
misp-projectmisp

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • misp-project mispup to 2.5.45 inclusive

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

    • up to and including 2.5.45affected · semver

Same product

misp-project: all records

Other highest-scoring records for the same primary product.

  • CVE-2022-29528An issue was discovered in MISP before 2.4.158.
    40Plan
  • CVE-2021-41326In MISP before 2.4.148, app/Lib/Export/OpendataExport.php mishandles parameter data that is used in a shell_exec call.
    40Plan
  • CVE-2018-19908An issue was discovered in MISP 2.4.9x before 2.4.99.
    40Plan

Published before and after this one in the same product

  • ← EarlierCVE-2026-86440Sep 7, 2026 · MISP Dashboard Button Widget Allows Stored XSS via Unsafe javascript: and Backslash URLs
    20Monitor
  • ← EarlierCVE-2026-86441Sep 7, 2026 · MISP Dashboard Organisation Widgets Bypass Organisation-Index Restrictions and Expose Hidden Organisation Data
    9Monitor
  • ← EarlierCVE-2026-86451Sep 7, 2026 · MISP Event Graph Object Reference Lookup Exposes References from Unauthorized Objects
    21Monitor

Remediation

Which version to upgrade to

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

No fix version is recorded for this entry. Check the references for vendor advisories.

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-2026-863470 days apartMISP Missing Authorization on Template File Upload Allows Authenticated Disk Exhaustion
    28Monitor
  • CVE-2026-9137110 days apartCSP Report Endpoint Log Flooding in MISP via Incorrect Size Limit
    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 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
None
User interaction
None
Scope
X

Weakness class (CWE)

CWE-400 · Uncontrolled Resource Consumption

CVSS vector

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

Code that parses nested structures sets no depth or size limit. A small input can turn into a disproportionate processing load.

The bug in code

The whole CWE-400 class

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

Vulnerable

ts
function expand(node) {  return node.children.map(expand);}

Fixed

ts
const MAX_DEPTH = 32;function expand(node, depth = 0) {  if (depth > MAX_DEPTH) throw new Error("too deep");  return node.children.map((c) => expand(c, depth + 1));}

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

No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.

References

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

All records