CVE-2026-51302 Overview
CVE-2026-51302 is a use-after-free vulnerability [CWE-416] in SQLite 3.41 affecting the expression evaluation logic. The sqlite3ReleaseTempReg function releases temporary register resources prematurely. The subsequent exprComputeOperands function then accesses the already freed register memory. A remote attacker can trigger the flaw by supplying a crafted SQL statement to a database engine that parses attacker-controlled queries.
Critical Impact
Successful exploitation can cause denial of service, disclose sensitive process memory, or lead to arbitrary code execution in the context of the SQLite process.
Affected Products
- SQLite 3.41.0
- Applications embedding the affected SQLite library
- Services exposing SQL parsing to untrusted input
Discovery Timeline
- 2026-07-27 - CVE-2026-51302 published to NVD
- 2026-07-30 - Last updated in NVD database
Technical Details for CVE-2026-51302
Vulnerability Analysis
The vulnerability resides in SQLite's expression compiler in src/expr.c. During expression code generation, SQLite allocates temporary Virtual Database Engine (VDBE) registers to hold intermediate operand values. The sqlite3ReleaseTempReg routine returns these registers to the free pool once a subexpression is considered complete.
In the affected code path, sqlite3ReleaseTempReg releases a temporary register while a dependent operation remains pending. The exprComputeOperands function then dereferences the stale register descriptor. This produces a classic use-after-free condition on heap-managed metadata associated with the register.
Attackers who control SQL text can steer register allocation to reach the freed slot. Depending on heap layout, the freed memory may contain attacker-influenced data. This can convert the memory-safety error into information disclosure or arbitrary code execution within the SQLite process.
Root Cause
The defect is a lifetime management error between register release and operand computation. sqlite3ReleaseTempReg and exprComputeOperands disagree on which routine owns the register during expression finalization. No reference counting or barrier prevents access to the released slot before it is reused.
Attack Vector
Exploitation requires the attacker to submit a malicious SQL statement to the SQLite engine. Any application that accepts SQL from a network client, browser context, or file-imported schema exposes the vulnerable path. Authentication may be required depending on the front-end application, and the attack complexity is high because it depends on heap grooming to place useful data in the freed register.
No verified proof-of-concept has been published. See the GitHub CVE Advisory and the SQLite source for expr.c for technical context.
Detection Methods for CVE-2026-51302
Indicators of Compromise
- Unexpected crashes or SIGSEGV signals in processes linking libsqlite3 version 3.41.0.
- Application logs showing SQL parser errors immediately followed by process termination or restart.
- Anomalous SQL statements with deeply nested expressions or unusual operator combinations submitted by external clients.
Detection Strategies
- Inventory installed SQLite versions across endpoints, servers, and containers to identify 3.41.0 builds.
- Instrument applications with AddressSanitizer or heap-checking allocators in staging to surface use-after-free events in sqlite3ReleaseTempReg and exprComputeOperands.
- Alert on repeated SQL parser exceptions or engine restarts correlated with a single client source.
Monitoring Recommendations
- Forward SQLite-hosting process crash telemetry, core dumps, and Windows Error Reporting events to a central log store.
- Monitor query logs for high-entropy or malformed SQL originating from untrusted principals.
- Track outbound network activity from database-hosting processes to catch post-exploitation callbacks.
How to Mitigate CVE-2026-51302
Immediate Actions Required
- Identify all applications, containers, and embedded devices shipping SQLite 3.41.0 and prioritize internet-exposed instances.
- Restrict SQL input to trusted, parameterized queries and reject client-supplied raw SQL where possible.
- Enable process-level exploit mitigations such as ASLR, DEP, and heap hardening on hosts running affected SQLite builds.
Patch Information
No vendor advisory URL is listed in the enriched CVE data at publication time. Consult the upstream project at the SQLite source repository for updated releases and commit history addressing the register lifetime issue, and upgrade to a fixed SQLite version once available.
Workarounds
- Sandbox SQLite-hosting processes with seccomp, AppArmor, or equivalent to limit post-exploitation impact.
- Disable or gate features that accept external SQL, such as user-supplied query interfaces and imported schema files.
- Apply strict allowlists for SQL statement patterns at the application layer to block malformed expressions.
# Configuration example: verify the linked SQLite version on Linux hosts
ldconfig -p | grep libsqlite3
sqlite3 --version
# Expected: upgrade any host reporting 3.41.0 to a fixed release
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
