CVE-2026-61674
criticalpriority · track · 0EPSS 0.007 · 54 %ileDENLUSEPSS · scored 2026-10-27
Fluent Bit is a fast and lightweight logs, metrics, and traces processor for Linux, BSD, macOS, and Windows. From 0.11.0 until 5.0.8, plugins/out_forward/forward.c secure_forward_pong copies the server-controlled PONG[2] reason into the 32-byte stack buffer msg with memcpy without checking its MessagePack type or length. An attacker who controls or can impersonate an out_forward Secure Forward destination configured with Shared_Key or Empty_Shared_Key can send an oversized reason during the first handshake and overwrite stack control data. Protected builds reliably terminate, while builds without a stack canary or with a disclosure can allow remote code execution as the Fluent Bit process user. When the opt-in --supervisor mode is used, fork-only respawns preserve the canary and address layout, allowing repeated crash-or-survive probes to support code execution on a hardened build; ordinary exec-based or service-manager restarts do not preserve that state. This issue is fixed in version 5.0.8.
cvss
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · high–critical · 7.2–9.2
ssvc
A stakeholder decision — act, attend, or track — from exploitation and impact.
weaknesses
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affected products (34)
Products and version ranges known to be affected.
advisories (4)
Vendor and ecosystem advisories describing this.
- NCSC-2026-0444Kwetsbaarheden verholpen in Oracle CommunicationsNL2026-10-21csaf · ncsc_nlNL
Oracle heeft 110 kwetsbaarheden verholpen in diverse Oracle Communications-producten, waaronder Oracle Communications Unified Assurance, Oracle Communications Cloud Native Core Security Edge Protection Proxy, Oracle Communications Service Catalog and Design en Oracle Communications Operations Monitor.
- WID-SEC-W-2026-3502Fluent Bit: Schwachstelle ermöglicht Ausführen von beliebigem Programmcode mit AdministratorrechtenDeutsch2026-09-21csaf · cert_bundDE
Ein entfernter, anonymer Angreifer kann eine Schwachstelle in Fluent Bit ausnutzen, um beliebigen Programmcode mit Administratorrechten auszuführen oder einen Denial-of-Service-Zustand herbeizuführen.
- WID-SEC-W-2026-4090Oracle Communications: Mehrere SchwachstellenDeutsch2026-10-20csaf · cert_bundDE
Ein entfernter, anonymer oder authentisierter Angreifer kann mehrere Schwachstellen in Oracle Communications ausnutzen, um die Vertraulichkeit, Integrität und Verfügbarkeit zu gefährden.
- BIT-fluent-bit-2026-61674Fluent Bit: Remote stack buffer overflow in Fluent Bit `out_forward` Secure-Forward `PONG` handler2026-09-29vendor · osvUS
Fluent Bit is a fast and lightweight logs, metrics, and traces processor for Linux, BSD, macOS, and Windows. From 0.11.0 until 5.0.8, plugins/out_forward/forward.c secure_forward_pong copies the server-controlled PONG[2] reason into the 32-byte stack buffer msg with memcpy without checking its MessagePack type or length. An attacker who controls or can impersonate an out_forward Secure Forward destination configured with Shared_Key or Empty_Shared_Key can send an oversized reason during the first handshake and overwrite stack control data. Protected builds reliably terminate, while builds without a stack canary or with a disclosure can allow remote code execution as the Fluent Bit process user. When the opt-in --supervisor mode is used, fork-only respawns preserve the canary and address layout, allowing repeated crash-or-survive probes to support code execution on a hardened build; ordinary exec-based or service-manager restarts do not preserve that state. This issue is fixed in version 5.0.8.
also known as (1)
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sources
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references (4) nvd
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