A Denial of Service (DoS) vulnerability exists in the Protobuf PHP library during the parsing of untrusted input. Maliciously structured messages—specifically those containing negative varints or deep recursion—can be used to crash the application, impacting service availability.

There are packages installed that are affected by a vulnerability referenced in the following CVE:

  - A Denial of Service (DoS) vulnerability exists in the Protobuf PHP library during the parsing of untrusted
    input. Maliciously structured messages—specifically those containing negative varints or deep
    recursion—can be used to crash the application, impacting service availability. (CVE-2026-6409)

An update of the protobuf package has been released.

The version of CBL-Mariner Releases installed on the remote Azure Linux 3.0 host is prior to tested version. It is, therefore, affected by a vulnerability as referenced in the CVE-2026-6409 advisory.

  - A Denial of Service (DoS) vulnerability exists in the Protobuf PHP library during the parsing of untrusted     input. Maliciously structured messagesspecifically those containing negative varints or deep     recursioncan be used to crash the application, impacting service availability. (CVE-2026-6409)

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - A Denial of Service (DoS) vulnerability exists in the Protobuf PHP library during the parsing of untrusted     input. Maliciously structured messagesspecifically those containing negative varints or deep     recursioncan be used to crash the application, impacting service availability. (CVE-2026-6409)

Note that Nessus relies on the presence of the package as reported by the vendor.

ID	Name	Product	Family	Type	Severity
460984	Echo: protobuf: security update to 3.21.12-11+e3	Tenable Cloud Security	Echo Local Security Checks	Local	high
460984	Echo: protobuf: security update to 3.21.12-11+e3	Tenable Self-Hosted Container Security	Echo Local Security Checks	Local	high
334130	Photon OS 5.0: Protobuf PHSA-2026-5.0-91-0849	Nessus	PhotonOS Local Security Checks	Local	high
315092	Photon OS 4.0: Protobuf PHSA-2026-4.0-1019	Nessus	PhotonOS Local Security Checks	Local	high
314918	Photon OS 5.0: Protobuf PHSA-2026-5.0-0849	Nessus	PhotonOS Local Security Checks	Local	high
310265	Azure Linux 3.0 Security Update: CBL-Mariner Releases (CVE-2026-6409)	Nessus	Azure Linux Local Security Checks	Local	high
306841	Linux Distros Unpatched Vulnerability : CVE-2026-6409	Nessus	Misc.	Local	high

Detections

Analytics

CVE-2026-6409

high

Tenable Plugins

high

high

high

high

high

high

high