CVE-2026-27890— Firebird has Pre-Auth DOS when Processing Out of Order CNCT_specific_data Segments
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I. Basic Information for CVE-2026-27890
Vulnerability Information
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Vulnerability Title
Firebird has Pre-Auth DOS when Processing Out of Order CNCT_specific_data Segments
Source: NVD (National Vulnerability Database)
Vulnerability Description
Firebird is an open-source relational database management system. In versions prior to 5.0.4, 4.0.7 and 3.0.14, when processing CNCT_specific_data segments during authentication, the server assumes segments arrive in strictly ascending order. If segments arrive out of order, the Array class's grow() method computes a negative size value, causing a SIGSEGV crash. An unauthenticated attacker who knows only the server's IP and port can exploit this to crash the server. This issue has been fixed in versions 5.0.4, 4.0.7 and 3.0.14.
Source: NVD (National Vulnerability Database)
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H
Source: NVD (National Vulnerability Database)
Vulnerability Type
内存缓冲区边界内操作的限制不恰当
Source: NVD (National Vulnerability Database)
Vulnerability Title
Firebird 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Firebird是Firebird基金会的一套开源跨平台的提供多个ANSI SQL-92功能的关系型数据库管理系统。 Firebird 5.0.4之前版本、4.0.7之前版本和3.0.14之前版本存在安全漏洞，该漏洞源于处理身份验证中的CNCT_specific_data段时假设顺序严格递增，可能导致计算负大小值并引发服务器崩溃。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)
Affected Products
| Vendor | Product | Affected Versions | CPE | Subscribe |
|---|---|---|---|---|
| FirebirdSQL | firebird | >= 3.0.0, < 3.0.14 | - |
II. Public POCs for CVE-2026-27890
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|---|
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- Release Firebird 4.0.7 · FirebirdSQL/firebird · GitHubx_refsource_MISC
- https://nvd.nist.gov/vuln/detail/CVE-2026-27890
Same Patch Batch · FirebirdSQL · 2026-04-17 · 9 CVEs total
| CVE-2026-40342 | 10.0 CRITICAL | Firebird: Path Traversal + Arbitrary File Write Leads to Remote Code Execution |
| CVE-2026-28224 | 8.2 HIGH | Firebird Null Pointer Dereference via CryptCallback causes DOS |
| CVE-2025-65104 | 7.9 HIGH | Firebird: Information leak vulnerability in firebird3 client when used with newer server |
| CVE-2026-35215 | 7.5 HIGH | Firebird: DoS via malicious slice descriptor in slice packet |
| CVE-2026-34232 | 7.5 HIGH | Firebird: DoS via `op_response` packet from client |
| CVE-2026-28212 | 7.5 HIGH | Firebird has potential server crash via null pointer dereference when processing op_slice |
| CVE-2026-33337 | 7.5 HIGH | Firebird has a buffer overflow when parsing corrupted slice packets |
| CVE-2026-28214 | Firebird server hangs when using specific clumplet on batch creation |
IV. Related Vulnerabilities
Same product: firebird
- CVE-2026-40342
Firebird: Path Traversal + Arbitrary File Write Leads to Rem - CVE-2026-35215
Firebird: DoS via malicious slice descriptor in slice packet - CVE-2026-34232
Firebird: DoS via `op_response` packet from client - CVE-2026-33337
Firebird has a buffer overflow when parsing corrupted slice - CVE-2026-28224
Firebird Null Pointer Dereference via CryptCallback causes D
Same vendor: FirebirdSQL
- CVE-2026-40342
Firebird: Path Traversal + Arbitrary File Write Leads to Rem - CVE-2026-35215
Firebird: DoS via malicious slice descriptor in slice packet - CVE-2026-34232
Firebird: DoS via `op_response` packet from client - CVE-2026-33337
Firebird has a buffer overflow when parsing corrupted slice - CVE-2026-28224
Firebird Null Pointer Dereference via CryptCallback causes D
Same weakness: CWE-119
- CVE-2026-22167
GPU DDK - Cache resident PM buffers writable by other GPU re - CVE-2026-34864
Huawei HarmonyOS 安全漏洞 - CVE-2026-4149
Sonos Era 300 SMB Response Out-Of-Bounds Access Remote Code - CVE-2026-34988
Wasmtime leaks data between pooling allocator instances - CVE-2026-39892
cryptography has a buffer overflow if non-contiguous buffers
V. Comments for CVE-2026-27890
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