EUVD-2026-40326
GHSA-v555-5g3c-vq2x
Severity by source
AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Description requires SQL execution privileges (PR:L not PR:N); AC:H retained because the specific seqscan+sort optimizer path must be triggered; no confidentiality or integrity impact.
Primary rating from Vendor (openGauss).
CVSS VectorVendor: openGauss
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Lifecycle Timeline
1DescriptionCVE.org
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。
AnalysisAI
Heap-use-after-free in openGauss 7.0.0-RC1 and RC2 allows a database user with SQL execution privileges to crash the backend process by crafting a to_timestamp() call with NLS parameters that triggers the seqscan+sort execution path. The nls_fmt_str pointer is stored in session context but allocated within SeqScan's expression memory context, which is freed upon scan completion; subsequent access by timestamp_out() via CheckNlsFormat() dereferences the dangling pointer. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitation requires an authenticated database session with SQL execution privileges on the openGauss instance - the description explicitly states this precondition ('具备数据库 SQL 执行权限'). … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The vendor-assigned CVSS 5.9 (AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H) contains a notable inconsistency: the description explicitly states exploitation requires database SQL execution privileges ('攻击者在具备数据库 SQL 执行权限的情况下'), yet the vector encodes PR:N (no privileges). … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | An attacker holding a valid database account on an openGauss 7.0.0-RC1 or RC2 instance submits a SELECT statement that calls to_timestamp() with an NLS format parameter in a way that causes the query planner to choose a seqscan followed by a sort operation - for example, scanning a large table without an appropriate index while converting a timestamp column. When the SeqScan node completes and its memory context is freed, the subsequent timestamp_out() call dereferences the now-freed nls_fmt_str pointer, crashing the backend process and terminating the attacker's connection along with any in-flight transaction on that backend. … |
| Remediation | Vendor-released patch: openGauss-server 7.0.0-RC3. … Detailed patch versions, workarounds, and compensating controls in full report. |
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Same weakness CWE-416 – Use After Free
View allSame technique Memory Corruption
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External POC / Exploit Code
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