CVE-2026-33278

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Source
https://cve.org/CVERecord?id=CVE-2026-33278
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-33278.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2026-33278
Downstream
ALPINE (1)
ALSA (2)
AZL (1)
CLSA (6)
DEBIAN (1)
ECHO (1)
OESA (5)
openSUSE (2)
RHSA (3)
RLSA (2)
ROOT (2)
SUSE (6)
UBUNTU (1)
Related
ALSA (2)
openSUSE (2)
SUSE (6)
Published
2026-05-20T10:16:26Z
Modified
2026-10-24T14:39:20Z
Severity
  • 9.8 (Critical) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H CVSS Calculator
Summary
[none]
Details

NLnet Labs Unbound 1.19.1 up to and including version 1.25.0 has a vulnerability in the DNSSEC validator that enables denial of service and possible remote code execution as a result of deep copying a data structure and erroneously overwriting a destination pointer. An adversary can exploit the vulnerability by controlling a malicious signed zone and querying a vulnerable Unbound. When DS sub-queries need to suspend validation due to NSEC3 computational budget exhaustion (introduced in Unbound 1.19.1), Unbound deep-copies response messages to preserve them across memory region teardown. A struct-assignment bug overwrites the destination's pointer with the source's pointer. After the sub-query region is freed, the resumed validator dereferences this dangling pointer, triggering a crash or potentially enabling arbitrary code execution. Unbound 1.25.1 contains a patch with a fix to preserve the correct pointer when deep copying the data structure.

References

Affected packages

Git / github.com/nlnetlabs/unbound

Affected ranges

Type
GIT
Repo
https://github.com/nlnetlabs/unbound
Events
Introduced
c6dd1e116df75242a0c032295c152f06c721b3cd
Fixed
75b6dba593d4fff000434cd64807c6ebd50bd244
Database specific
Show details 
{
    "extracted_events": [
        {
            "cpe": "cpe:2.3:a:nlnetlabs:unbound:*:*:*:*:*:*:*:*",
            "range": [
                {
                    "introduced": "1.19.1"
                },
                {
                    "fixed": "1.25.1"
                }
            ],
            "source": "CPE_RANGE"
        }
    ]
}

Database specific

source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-33278.json"
vanir_signatures 
[
    {
        "deprecated": false,
        "digest": {
            "function_hash": "26148135886169857913239956572075736548",
            "length": 1502
        },
        "id": "CVE-2026-33278-7cb89fac",
        "signature_type": "Function",
        "signature_version": "v1",
        "source": "https://github.com/nlnetlabs/unbound/commit/75b6dba593d4fff000434cd64807c6ebd50bd244",
        "target": {
            "file": "services/rpz.c",
            "function": "rpz_callback_from_iterator_module"
        }
    },
    {
        "deprecated": false,
        "digest": {
            "line_hashes": [
                "108481287081154918060659085654141150584",
                "73953166938600086918224773195867549742",
                "15251087855327528788980657535362970158",
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                "112058947495561481565691171486557666856",
                "238258467286774268681997190612827183971",
                "126648031849056156900266153546629664662",
                "335401097143186200364020904286165936708",
                "336096779053276656395004922884987906159",
                "248876396313049466881138460638611830858",
                "293135123655960925553682804594622081358",
                "298612071867479354827766089224387452786",
                "217265304546593372824910550975155656654",
                "13292601781282786772501437491204364169",
                "281286782737850123600796590480125479595",
                "74511316679551775089931390035715335201",
                "161066344018382590627892027575409612852",
                "226343512543910522766563315515650712879"
            ],
            "threshold": 0.9
        },
        "id": "CVE-2026-33278-a3b17d2e",
        "signature_type": "Line",
        "signature_version": "v1",
        "source": "https://github.com/nlnetlabs/unbound/commit/75b6dba593d4fff000434cd64807c6ebd50bd244",
        "target": {
            "file": "services/rpz.c"
        }
    }
]
vanir_signatures_modified 
"2026-10-24T14:39:20Z"