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NVD / CVE Program· CNA EEF

CVE-2026-55736: Private action arguments can be set by user input in Ash

Noroxi assessment

Priority: Monitor (action score 23/100)

  • 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: 0.22% (FIRST EPSS).
  • Someone with local access to the system can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: ash-project ash 3.29.3, d9b3100219b3ea86d73202bf7368c03a7688efea.

Low priority for now. Upgrade to ash-project ash 3.29.3, d9b3100219b3ea86d73202bf7368c03a7688efea 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

Improperly Controlled Modification of Dynamically-Determined Object Attributes vulnerability in ash-project ash allows a user to set the value of a private action argument that is intended to be controlled only by trusted server-side code. Action arguments declared with public?: false are meant to be set internally (for example via Ash.Changeset.set_private_argument/3) and must not be settable from end-user input. When a changeset is built from a parameter map, Ash filters out private arguments, but the filtering is incomplete. In the regular changeset path (for_create, for_update, for_destroy), private arguments are stripped only when the parameter key is an atom. When the key is a binary (string), as is the case for user-supplied parameters, the private argument is kept and the user controls its value. In the atomic path (Ash.Changeset.fully_atomic_changeset/4, also reached through atomic and bulk updates), private arguments are not stripped at all, regardless of whether the key is an atom or a binary. An attacker who can submit parameters to an action that defines a private argument can therefore inject a value for that argument. Depending on how the application uses the argument (for example an acting_user_id driving authorization or record ownership), this can lead to an integrity violation or privilege escalation. This issue affects ash: from 3.0.0 before 3.29.3.

MediumCVSS 5.9 · v4.0—No exploit Fix available
Published
Jun 23, 2026
Updated
Oct 25, 2026
EPSS
0.2% · 13th percentile

Report tools

JSON

Action score

23

Monitor

Low priority for now.

CVSS
23 / 40 · 5.9 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

CISA SSVC decision

Exploitation
proof of concept
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · EEF
5.9
NVD has not scored this yet; the score shown is the CNA’s.

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

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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?

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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 (EEF). Independent of NVD's CPE analysis and usually ahead of it.

  • ash-project ash

    • 3.0.0 and later · before 3.29.3affected · semver
    • 5967ed3a483ab949866e6d7b043b043e61703f17 and later · before d9b3100219b3ea86d73202bf7368c03a7688efeaaffected · git

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Hexashfrom 3.0.0 · before 3.29.33.29.3

Same product

ash-project: all records

Other highest-scoring records for the same primary product.

  • CVE-2025-48044Authorization bypass when bypass policy condition evaluates to true
    34Monitor
  • CVE-2025-48043Bypass and runtime policies that can never pass may be incorrectly applied in filter authorization
    34Monitor
  • CVE-2026-94201Filtering an :atom attribute with unsafe_to_atom? can exhaust the BEAM atom table in Ash
    32Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2025-48042Sep 7, 2025 · Before action hooks may execute in certain scenarios despite a request being forbidden
    28Monitor
  • Later →CVE-2026-70395Aug 9, 2026 · Predicate injection in manage_relationship belongs_to lookup discloses secret lookup keys in Ash
    8Monitor
  • Later →CVE-2026-82734Sep 1, 2026 · Non-finite Infinity/NaN decimal values bypass bounds constraints in Ash.Type.Decimal
    8Monitor

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
ash-project ash3.29.3Vendor (CNA)
ash-project ashd9b3100219b3ea86d73202bf7368c03a7688efeaVendor (CNA)
Hex:ash3.29.3Package registry (OSV)

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.

No history yet (it accumulates with the daily EPSS job).

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-2026-9347794 days apartPrivate action arguments can be set by user input on the bulk destroy and bulk update paths in Ash
    23Monitor

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

  • Someone with local access to the system 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
Local
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
X

Weakness class (CWE)

CWE-915 · Improperly Controlled Modification of Dynamically-Determined Object Attributes

CVSS vector

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

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

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References

Show all references (3 more)

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

All records