CVE-2026-14178
MediumCVSS 5.9Summary
In openGauss, when processing to_timestamp calls with NLS parameters, to_timestamp_with_fmt_nls() stores nls_fmt_str in u_sess->parser_cxt.nls_fmt_str. In the seqscan + sort execution path, this string is allocated in the SeqScan expression context; after SeqScan completes, the memory context is reset, but the output phase timestamp_out() still accesses u_sess->parser_cxt.nls_fmt_str via CheckNlsFormat(), causing a heap-use-after-free. An attacker with SQL execution privileges can craft a specific to_timestamp(..., ..., nlsparam) query to trigger this, leading to backend process crash and denial of service.
Risk Assessment
The risk is that an attacker with SQL privileges can cause a backend process crash, disrupting database service availability (denial of service). In ASan/Memcheck environments, this may cause database exit, while in production it can lead to system instability.
Recommendation
Immediately upgrade openGauss-server to version 7.0.0-RC3 or later, as versions 7.0.0-RC1 and 7.0.0-RC2 are vulnerable and will not receive individual patches. The issue is fixed in the newer version.
Original NVD description (English source)
openGauss 在处理带 NLS 参数的 to_timestamp 调用时，to_timestamp_with_fmt_nls() 会将 nls_fmt_str 保存到 u_sess->parser_cxt.nls_fmt_str。在 seqscan + sort 执行路径下，该字符串原本被分配在 SeqScan 的表达式上下文中；当 SeqScan 完成后，该内存上下文会被 reset，但后续结果输出阶段 timestamp_out() 仍会通过 CheckNlsFormat() 访问 u_sess->parser_cxt.nls_fmt_str，导致访问已释放内存。攻击者在具备数据库 SQL 执行权限的情况下，可构造特定 to_timestamp(..., ..., nlsparam) 查询触发 heap-use-after-free。在 ASan/Memcheck 环境下表现为数据库服务退出；在实际运行环境中可能造成后端进程异常退出，影响数据库服务可用性，形成拒绝服务风险。该问题在openGauss-server-7.0.0-RC1版本和openGauss-server-7.0.0-RC2版本存在，目前已在openGauss-server-7.0.0-RC3版本修复。由于 openGauss-server-7.0.0-RC1版本和openGauss-server-7.0.0-RC2均为创新版本，不会发布针对性补丁包，涉及版本升级至 openGauss-server-7.0.0-RC3或更新版本即可。