CVE-2026-40209

An attacker might be able to cause outgoing TCP connections to backend to be stuck until a timeout occurs instead of being released immediately, by sending IXFR queries. This could be used to cause a denial of service if there is a limit to the number of concurrent connections to this backend, or if the process runs out of file descriptors.

Database specific

{
    "cna_assigner": "OX",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/40xxx/CVE-2026-40209.json"
}

References

Affected packages

Git / github.com/powerdns/pdns

Affected ranges

Type

GIT

Repo

https://github.com/powerdns/pdns

Events

Introduced

298a9d67fb760a12eabe89164f92fb814572aea8

Fixed

3348a4f5e1ea95ed90ad6bbdf9c7f12be72e9bfc

Introduced

89747e81bc60d7950276d5fda3ca669fa81b7cf9

Fixed

5bd46a775a7d72376c6a22b2313173a187d439dd

Database specific

{
    "source": "AFFECTED_FIELD",
    "extracted_events": [
        {
            "introduced": "1.9.0"
        },
        {
            "fixed": "1.9.15"
        },
        {
            "introduced": "2.0.0"
        },
        {
            "fixed": "2.0.7"
        }
    ]
}

Affected versions

dnsdist-1.*

dnsdist-1.9.0

dnsdist-1.9.1

dnsdist-1.9.10

dnsdist-1.9.11

dnsdist-1.9.14

dnsdist-1.9.2

dnsdist-1.9.3

dnsdist-1.9.4

dnsdist-1.9.5

dnsdist-1.9.6

dnsdist-1.9.7

dnsdist-1.9.8

dnsdist-1.9.9

dnsdist-2.*

dnsdist-2.0.0

dnsdist-2.0.1

dnsdist-2.0.2

dnsdist-2.0.5

dnsdist-2.0.6

Database specific

source

"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-40209.json"

vanir_signatures

[
    {
        "source": "https://github.com/powerdns/pdns/commit/3348a4f5e1ea95ed90ad6bbdf9c7f12be72e9bfc",
        "signature_type": "Function",
        "signature_version": "v1",
        "target": {
            "function": "feed",
            "file": "ext/yahttp/yahttp/reqresp.cpp"
        },
        "digest": {
            "function_hash": "175905571297022484819797437345790495302",
            "length": 6030.0
        },
        "id": "CVE-2026-40209-39fe2f8e",
        "deprecated": false
    },
    {
        "source": "https://github.com/powerdns/pdns/commit/3348a4f5e1ea95ed90ad6bbdf9c7f12be72e9bfc",
        "signature_type": "Line",
        "signature_version": "v1",
        "target": {
            "file": "ext/yahttp/yahttp/reqresp.cpp"
        },
        "digest": {
            "line_hashes": [
                "146073261330685155030523374299187221356",
                "139999140489202660150035160998558678530",
                "260398486233326308600521181399778936346",
                "178066237530059398734757326132960946649"
            ],
            "threshold": 0.9
        },
        "id": "CVE-2026-40209-5ad4401b",
        "deprecated": false
    },
    {
        "source": "https://github.com/powerdns/pdns/commit/5bd46a775a7d72376c6a22b2313173a187d439dd",
        "signature_type": "Line",
        "signature_version": "v1",
        "digest": {
            "line_hashes": [
                "146073261330685155030523374299187221356",
                "139999140489202660150035160998558678530",
                "260398486233326308600521181399778936346",
                "178066237530059398734757326132960946649"
            ],
            "threshold": 0.9
        },
        "id": "CVE-2026-40209-8834b793",
        "target": {
            "file": "ext/yahttp/yahttp/reqresp.cpp"
        },
        "deprecated": false
    },
    {
        "source": "https://github.com/powerdns/pdns/commit/5bd46a775a7d72376c6a22b2313173a187d439dd",
        "signature_type": "Function",
        "signature_version": "v1",
        "target": {
            "function": "feed",
            "file": "ext/yahttp/yahttp/reqresp.cpp"
        },
        "digest": {
            "function_hash": "237403263111315157988973709551044007080",
            "length": 6074.0
        },
        "id": "CVE-2026-40209-f428faf8",
        "deprecated": false
    }
]

vanir_signatures_modified

"2026-07-21T23:35:49Z"