In some circumstances, when DNSdist is configured to allow an unlimited number of queries on a single, incoming TCP connection from a client, an attacker can cause a denial of service by crafting a TCP exchange that triggers an exhaustion of the stack and a crash of DNSdist, causing a denial of service. The remedy is: upgrade to the patched 1.9.10 version. A workaround is to restrict the maximum number of queries on incoming TCP connections to a safe value, like 50, via the setMaxTCPQueriesPerConnection setting. We would like to thank Renaud Allard for bringing this issue to our attention.

The remote Ubuntu 22.04 LTS / 24.04 LTS / 25.10 host has a package installed that is affected by multiple vulnerabilities as referenced in the USN-8037-1 advisory.

    It was discovered that HTTP/2, which is used/vendored by DNSdist, did not properly account for resources     when handling client-triggered stream

    resets. An attacker could possibly use this issue to cause a

    denial of service. (CVE-2025-8671)

    It was discovered that DNSdist did not properly manage memory limits when handling an unlimited number of     queries on a single TCP connection. An

    attacker could possibly use this issue to cause a denial of service. (CVE-2025-30193)

    It was discovered that DNSdist, when configured with the nghttp2 library, did not correctly process     certain DNS over HTTPS queries. An attacker could possibly use this cause a denial of service.
    (CVE-2025-30187)

Tenable has extracted the preceding description block directly from the Ubuntu security advisory.

Note that Nessus has not tested for these issues 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.

  - In some circumstances, when DNSdist is configured to allow an unlimited number of queries on a single,     incoming TCP connection from a client, an attacker can cause a denial of service by crafting a TCP     exchange that triggers an exhaustion of the stack and a crash of DNSdist, causing a denial of service. The     remedy is: upgrade to the patched 1.9.10 version. A workaround is to restrict the maximum number of     queries on incoming TCP connections to a safe value, like 50, via the setMaxTCPQueriesPerConnection     setting. We would like to thank Renaud Allard for bringing this issue to our attention. (CVE-2025-30193)

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

The remote SUSE Linux SLES15 host has a package installed that is affected by a vulnerability as referenced in the SUSE- SU-2025:01792-1 advisory.

    - CVE-2025-30193: stack exhaustion when processing too many queries on incoming TCP connections leads to a       denial-of-service (bsc#1243378).

Tenable has extracted the preceding description block directly from the SUSE security advisory.

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

The remote SUSE Linux SLED15 / SLED_SAP15 / SLES15 / SLES_SAP15 / openSUSE 15 host has a package installed that is affected by a vulnerability as referenced in the SUSE-SU-2025:01745-1 advisory.

    - CVE-2025-30193: stack exhaustion when processing too many queries on incoming TCP connections leads to a       denial-of-service (bsc#1243378).

Tenable has extracted the preceding description block directly from the SUSE security advisory.

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

The remote SUSE Linux SLED15 / SLED_SAP15 / SLES15 / SLES_SAP15 host has a package installed that is affected by multiple vulnerabilities as referenced in the SUSE-SU-2025:01743-1 advisory.

    Update to version 1.9.10.

    - CVE-2025-30194: illegal memory access (double-free) when processing specially crafted DoH exchanges     leads to a       denial-of-service (bsc#1242028).
    - CVE-2025-30193: stack exhaustion when processing too many queries on incoming TCP connections leads to a       denial-of-service (bsc#1243378).

Tenable has extracted the preceding description block directly from the SUSE security advisory.

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

The remote Fedora 41 host has a package installed that is affected by multiple vulnerabilities as referenced in the FEDORA-2025-0c238cf731 advisory.

    Updated to 1.9.10, this fixes CVE-2025-30193: Denial of service via crafted TCP exchange

Tenable has extracted the preceding description block directly from the Fedora security advisory.

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

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

  - In some circumstances, when DNSdist is configured to allow an unlimited number of queries on a single,
    incoming TCP connection from a client, an attacker can cause a denial of service by crafting a TCP
    exchange that triggers an exhaustion of the stack and a crash of DNSdist, causing a denial of service. The
    remedy is: upgrade to the patched 1.9.10 version. A workaround is to restrict the maximum number of
    queries on incoming TCP connections to a safe value, like 50, via the setMaxTCPQueriesPerConnection
    setting. We would like to thank Renaud Allard for bringing this issue to our attention. (CVE-2025-30193)

ID	Name	Product	Family	Severity
299040	Ubuntu 22.04 LTS / 24.04 LTS / 25.10 : DNSdist vulnerabilities (USN-8037-1)	Nessus	Ubuntu Local Security Checks	high
250762	Linux Distros Unpatched Vulnerability : CVE-2025-30193	Nessus	Misc.	high
237695	SUSE SLES15 Security Update : dnsdist (SUSE-SU-2025:01792-1)	Nessus	SuSE Local Security Checks	high
237547	SUSE SLED15 / SLES15 / openSUSE 15 Security Update : dnsdist (SUSE-SU-2025:01745-1)	Nessus	SuSE Local Security Checks	high
237540	SUSE SLED15 / SLES15 Security Update : dnsdist (SUSE-SU-2025:01743-1)	Nessus	SuSE Local Security Checks	high
237524	Fedora 41 : dnsdist (2025-0c238cf731)	Nessus	Fedora Local Security Checks	high
427734	Alpine: multiple dnsdist packages: security update to 1.9.10-r0	Tenable Cloud Security	Alpine Linux Local Security Checks	high
427734	Alpine: multiple dnsdist packages: security update to 1.9.10-r0	Tenable Self-Hosted Container Security	Alpine Linux Local Security Checks	high

Detections

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CVE-2025-30193

high

Tenable Plugins

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high

high

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high