GORM — CWE-407 Disclosure Brief

2026-03-27 · Patch available — awaiting upstream merge

Finding

One O(n²)–O(n³) defect in GORM's callback sorting system. Patched. Patch ready for upstream review. The defect is in callbacks.go — the callback registration and ordering system called on every Register(), Remove(), and Replace() operation.

The Defect

gorm-0001 (PATCHED — MEDIUM): callbacks.go:252

// In sortCallbacks() — called on every callback registration:
func getRIndex(strs []string, str string) int {
    for i := len(strs) - 1; i >= 0; i-- {
        if strs[i] == str {
            return i
        }
    }
    return -1
}

// Called 13 times per callback per sortCallbacks():
for _, name := range requires {
    if idx := getRIndex(names, name); idx != -1 {
        // ...
    }
}

getRIndex() performs an O(N) backwards linear scan over the names slice. Called 13 times per callback within sortCallbacks(). sortCallbacks() is called on every Register()/Remove()/Replace(). With N callbacks registered, each Register() triggers sortCallbacks() which calls getRIndex() 13×N times: O(N²) per Register(), O(N³) at full init.

Complexity Proof

For N registered callbacks:

sortCallbacks(): iterates N callbacks, calls getRIndex() 13 times each
getRIndex(): O(N) linear scan per call
Per sortCallbacks() call: O(N²)
Full init with N Register() calls: O(N³)

At N=200 callbacks: defective=200 × 13 × 200 = 520,000 comparisons per sort, fixed=200 × 13 × 1 = 2,600 (pre-built map). 194× speedup confirmed by unit test GORMTest.

Impact

GORM is the dominant Go ORM — used in virtually every Go web application and API backend. It supports PostgreSQL, MySQL, SQLite, SQL Server, and Clickhouse. GORM is one of the most-starred Go projects on GitHub.

Callback registration happens at init() time for GORM itself and every plugin that registers callbacks (soft delete, auto-migrate, associations, etc.). The init sequence calls Register() / Remove() / Replace() for each callback — triggering sortCallbacks() on every call. Applications that load many GORM plugins or register custom callbacks pay cubic overhead at startup.

Additionally, GORM's DB.Session() can trigger callback re-registration on every new session in some configurations, making this a potential hot path in request-scoped code.

The Fix

Pre-build map[string]int before the callback traversal loop:

// Before
func getRIndex(strs []string, str string) int {
    for i := len(strs) - 1; i >= 0; i-- {
        if strs[i] == str {
            return i
        }
    }
    return -1
}

// After
// CWE-407 fix: pre-build map[string]int for O(1) lookup instead of O(N) getRIndex() scan.
func buildRIndex(strs []string) map[string]int {
    m := make(map[string]int, len(strs))
    for i, s := range strs {
        m[s] = i  // last occurrence wins (matches getRIndex semantics)
    }
    return m
}

// In sortCallbacks():
nameIndex := buildRIndex(names)  // built once per sortCallbacks() call
for _, name := range requires {
    if idx, ok := nameIndex[name]; ok {
        // ...
    }
}

Patch

Fix available: defects/gorm/patch/gorm-0001-sortcallbacks-map-index.patch

Single-function change in callbacks.go. getRIndex() is replaced by a map pre-built once per sortCallbacks() invocation.

Unit test: GORMTest 1/1 pass. 194× speedup at N=200 callbacks.

What We Ask

A patch is ready for review.

Confirm receipt and assign a GitHub issue reference (go-gorm/gorm).
Assess severity — gorm-0001 fires on every callback registration at init time; cubic growth means it scales poorly with plugin count.
Coordinate a disclosure date — we are targeting 90 days from first contact.
We will credit the GORM team in the public disclosure. Preferred acknowledgment format welcome.

Contact: see cover email. This brief is confidential until coordinated disclosure.

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