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Fencer Vulns
medium 5.9

CVE-2026-77454 json

exists/2 predicate silently dropped on limited relationships with a parent() filter in AshSql

published 2026-08-30 2 mo ago modified 2026-09-08 2 mo ago also EEF-CVE-2026-77454 , EUVD-2026-68198 , GHSA-8v9m-8pxv-738c

cvss
5.9
version 4.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 7%
public exploits
0
none known

Summary

Incorrect Authorization vulnerability in ash-project ash_sql allows a caller to bypass a scoping or authorization filter expressed as exists/2 over a relationship that declares both a limit (or from_many?) and a parent(...)-referencing filter or sort.

AshSql.Join.related_query/3 skips the caller-supplied exists predicate for such relationships and delegates it to limit_from_many/5. When the relationship's own filter or sort references parent(...), limit_from_many/5 takes a branch that drops both the limit and the predicate, emitting a bare correlated EXISTS with no predicate. The check then matches any record that has any related row. Most severely, when the expression backs a policy (for example authorize_if expr(exists(memberships, user_id == ^actor(:id)))), the actor-scoping condition disappears and the policy passes for any actor with any related row.

This issue affects ash_sql: from 0.4.1 before 0.7.1.

Patch / fix

  • hex ash_sql 0.7.1
  • ash-project ash_sql 0.7.1

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
2 mo ago

Exploit prediction

0.18% chance of exploitation in the next 30 days, higher than 7% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/ash-project/ash_sql/security/advisories/GHSA-8v9m-8pxv-738c referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 4.0 5.9 CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N
CNA 4.0 5.9 CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:H/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

Affected packages

ecosystem package affected fixed in
hex ash_sql
>=0.4.1, <0.7.1
0.7.1

Affected products

  • ash-project ash_sql

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.