CVE Intelligence
Medium Access control

CVE-2026-93477 — Private action arguments can be set by user input on the bulk destroy and bulk update paths in Ash

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 on the bulk destroy and bulk update paths. Action arguments declared with public?: false are meant to be set only by trusted server-side code (for example via Ash.Changeset.set_private_argument/3) and must not be settable from end-user input. CVE-2026-55736 fixed the non-bulk changeset path to strip private arguments from user-supplied parameter maps, but the bulk destroy and bulk update paths were not covered. Ash.Actions.Destroy.Bulk.base_changeset/5 and Ash.Actions.Update.Bulk.base_changeset/5 match every key in the caller-supplied parameter map against all of the action's arguments with no public? check, then apply the matches to the base changeset. A caller who can submit parameters to a bulk destroy or bulk update action (for example through AshJsonApi, AshGraphql, or a controller that forwards request parameters to Ash.bulk_destroy/4 or Ash.bulk_update/4) can therefore set any private argument of that action, including one referenced by an arg(...) template in the action's changes or validations. Depending on how the application uses the argument (for example an acting_user_id driving authorization or record ownership, or audit metadata), this can lead to an integrity violation or privilege escalation. The fix requires public? in the argument matching on both bulk paths; private arguments remain settable server-side via the :private_arguments option. This issue affects ash: from 2.17.15 before 3.33.11.

Published Sep 25, 2026 · Updated Oct 15, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: EEF

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
  • 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
—
No EPSS score.
Affects
Ash-project
Ash
CVSS base
5.9
Medium · 2 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.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

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 (Ash-project Ash).
  2. No fix documented in the sources: reduce exposure and monitor the vendor advisory.
  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
Ash-project Ash ≥ 2.17.15 and < 3.33.11≥ 8c17434803b2e91de522bdfbd0ca918e5d5898df and < 6b7ac53a0a2532291eb940d7beaf0fbb2da6fc4f Vulnerable CVE Program (cve.org) e CISA ADP

Attack characteristics

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

Attack vector
Local
Attack complexity
Low
Attack requirements
Present
Privileges required
None
User interaction
None
Scope
X
Confidentiality (vulnerable system)
None
Integrity (vulnerable system)
High
Availability (vulnerable system)
None
Confidentiality (subsequent)
None
Integrity (subsequent)
None
Availability (subsequent)
None

Every base score collected

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

ScoreVersionSeverityExpl.ImpactScored by
5.9 CVSS 4.0 Medium — — 6b3ad84c-e1a6-4bf7-a703-f496b71e49db via NIST National Vulnerability Database
5.9 CVSS 4.0 Medium — — EEF via CVE Program (cve.org) e CISA ADP
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 (score shown at the top: 6b3ad84c-e1a6-4bf7-a703-f496b71e49db)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-915 · Mass Assignment

Other CVEs with this weakness →

Detection

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

  • Local/physical vector: focus on endpoint telemetry (EDR) from affected hosts.
  • Audit administrative actions and access to resources outside each user’s normal pattern.
endpoint telemetry (EDR)authentication logsapplication logs

Timeline

What happened to this CVE, newest first.

  • 2026
  • Affected products added · ash-project/ash
    Oct 15, 2026 · CVE Program (cve.org) e CISA ADP
  • SSVC assessment updated
    Oct 15, 2026 · CVE Program (cve.org) e CISA ADP
  • Record published
    Oct 15, 2026
  • CVSS changed · 5.9
    Oct 15, 2026 · NIST National Vulnerability Database
  • Source status changed · → Deferred
    Oct 15, 2026 · NIST National Vulnerability Database
  • Record created in this database
    Oct 15, 2026 · NIST National Vulnerability Database
  • CVE published
    Sep 25, 2026 · EEF

Source activity

Repeated readings are counted rather than listed.

  • 1× Official description updated · Oct 15, 2026 – Oct 15, 2026

References

5 on the record

Elsewhere on this site

Ash-project
every CVE for this vendor
Access control
same class
CWE-915
other pages naming this weakness

Related CVEs (same products)

  • CVE-2026-101028 Ash.count, Ash.exists and Ash.aggregate skip related resources' read policies in filters and sorts 6d
  • CVE-2026-94201 Filtering an :atom attribute with unsafe_to_atom? can exhaust the BEAM atom table in Ash 10d
  • CVE-2026-86338 Ash field policies do not filter-nil forbidden calculations and aggregates, enabling an information-disclosure oracle 29d
  • CVE-2026-82752 Ash string length constraints count graphemes, so a combining-mark string of any size passes max_length Sep 5, 2026
  • CVE-2026-82747 Ash.Policy.Authorizer returns records denied by a runtime read policy to any actor Sep 1, 2026
  • CVE-2026-82749 Ash relationship parent(...) filter degrades to an IS NULL match when the parent field is unresolved, leaking scoped records Sep 1, 2026

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 FIRST EPSS score.
  • No fixed version, patch or mitigation documented.
  • 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-2026-93477 is "Private action arguments can be set by user input on the bulk destroy and bulk update paths in Ash", rated Medium. It affects Ash (Ash-project); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 5.9 describes technical severity. 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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