CVE-2026-123571

Hickory DNS from 0.26.0 before 0.26.2 Panic via TSIG RDATA Decoding

CVSS 4.0 8.7 HIGHCVSS 3.1 7.5 HIGHEUVD CVSS 4.0 8.7 CVSS 4.0 · [email protected] · Secondary 8.7 HIGHCVSS 3.1 · [email protected] · Secondary 7.5 HIGHosv · severity unknownFixed by hickory-proto 0.26.2KEV status unknown

Original advisory

cve-program · CVE-2026-123571

Published

Hickory DNS from 0.26.0 before 0.26.2 contains an integer underflow vulnerability in TSIG RDATA decoding that allows remote attackers to trigger a panic via malformed records. Attackers can send a crafted TSIG record in DNS wire format to cause unchecked subtraction underflow, crashing builds with overflow checks enabled and causing denial of service.

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euvd · EUVD-2026-119456

Published

Read the publisher's advisory

nvd · CVE-2026-123571

Published

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osv · RUSTSEC-2026-0488

Published

When a TSIG record is decoded from the DNS wire format, its MAC length and "other data" length are checked against the end of the record data. If a check failed, the error value was built from `end_idx - decoder.index()`. For a malformed record the decoder can already be past `end_idx`, so this unsigned subtraction underflows. In builds with overflow checks enabled (the `dev` profile by default) the underflow panics, so a peer that sends a crafted TSIG record can crash the process. In builds without overflow checks the result wraps and is only used in the returned error. The fix returns a plain "insufficient bytes" error without the subtraction. It is in 0.26.2.

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Affected versions, risk and source history

cve-program · CVE-2026-123571

Published

hickory-dns

Vendor product

Publisher's version information

Shown as published. These rules are not interpreted as NuGet package version ranges.

{
                    "vendor": "hickory-dns",
                    "product": "hickory-dns",
                    "defaultStatus": "unaffected",
                    "packageURL": "pkg:cargo/hickory-proto",
                    "versions": [
                        {
                            "version": "0.26.0",
                            "status": "affected",
                            "versionType": "semver",
                            "lessThan": "0.26.2"
                        },
                        {
                            "version": "0.26.2",
                            "status": "unaffected",
                            "versionType": "semver"
                        }
                    ]
                }

Original source record · Cite this exact observation · Complete original publisher JSON

euvd · EUVD-2026-119456

Published

EUVD source date text has no stated timezone and is retained without inventing a UTC instant. Related bulletin membership is not an alias, common cause or applicability claim. A missing vector with a zero score is treated as unrated. Complete vendor/product and underlying source evidence remains in the original JSON.

Original publisher date fields

datePublished: Nov 8, 2026, 1:38:08 AM

dateUpdated: Nov 13, 2026, 3:04:27 AM

No normalized affected-package data is projected for this source revision. The original publisher record may contain additional product and version evidence; this does not establish that a package is unaffected.

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nvd · CVE-2026-123571

Published

NVD analysis and CPE criteria are source context, not proof that a package or your environment is affected. Complete affected data, logical configurations and SSVC are retained in the original JSON.

Source analysis status: Deferred

Weakness classifications: CWE-191

Original publisher date fields

published: 2026-11-08T02:16:49.990

lastModified: 2026-11-13T04:17:37.187

Original source record · Cite this exact observation · Complete original publisher JSON

osv · RUSTSEC-2026-0488

Published

hickory-proto

crates.io

SEMVER · introduced 0.26.0 → fixed 0.26.2

Original source record · Cite this exact observation · Complete original publisher JSON