CVE-2026-81318
LOW 2.1 PoC AVAILABLEIncorrect Authorization vulnerability in ash-project ash_sql allows a caller in a schema-based multitenant application to receive aggregate values computed from another tenant's rows. When an aggregate is computed over a distinct query, AshSql.AggregateQuery.add_single_aggs/5 rebuilds the outer query from query.from.source alone, which is only the {table, schema} tuple and does not carry query.prefix or query.from.prefix. For strategy(:context) multitenancy those hold the tenant schema, so the rebuilt outer query reads the repo's default schema while the inner correlated subquery still reads the tenant schema, and the two are joined only on primary key. The aggregate, and any relationship join added off the prefix-less binding, is then computed against the wrong tenant's rows. The neighbouring limit and exists branches instead wrap the query with subquery/1, which preserves the prefix. This issue affects ash_sql: from 0.1.0 before 0.7.1.
Public exploit or PoC code exists. Modeled probability is still low, but the barrier to attack is reduced — watch closely.
Exploitation likelihood
0.1%chance of exploitation in 30 days · 2nd percentile
Impact if exploited
2.1CVSS 4.0 · LOW
- ConfidentialityLow
- IntegrityNone
- AvailabilityNone
What an attacker needs
- ⚠Access: Requires local access to the host
- ✓Privileges: No account or privileges required
- ✓User interaction: No user interaction needed
- ✓Complexity: No special conditions — reliably repeatable
- ⚠Requirements: Specific conditions must be present
✓ lowers the bar for an attacker · ⚠ raises it
Proof of concept & exploit code
- reference https://github.com/ash-project/ash_sql/security/advisories/GHSA-ww8j-58rc-f8h3
- github-search Search GitHub for public PoC repos
Test against your own equipment
curl -s https://vulnpedia.com/cve/CVE-2026-81318/poc.jsonMachine-readable PoC index for this CVE (for automation).Listed for defensive triage, patch verification, and authorized testing on systems you own. Machine-readable: /cve/CVE-2026-81318/poc.json
Weakness (CWE)
- CWE-863: Incorrect Authorization
CVSS vector
CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
All CVSS metrics
- LOW 2.1 v4.0 · CNA Primary
CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N - LOW 2.1 v4.0 · NVD Secondary
CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/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