184 lines
7.6 KiB
JSON
184 lines
7.6 KiB
JSON
{
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"dataType": "CVE_RECORD",
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"dataVersion": "5.2",
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"cveMetadata": {
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"cveId": "CVE-2026-55991",
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"assignerOrgId": "206fc3a0-e175-490b-9eaa-a5738056c9f6",
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"state": "PUBLISHED",
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"assignerShortName": "NLnet Labs",
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"dateReserved": "2026-06-22T10:11:10.505Z",
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"datePublished": "2026-07-22T13:10:13.235Z",
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"dateUpdated": "2026-09-16T14:24:57.805Z"
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},
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"containers": {
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"cna": {
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"affected": [
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{
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"defaultStatus": "unaffected",
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"product": "Unbound",
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"vendor": "NLnet Labs",
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"versions": [
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{
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"lessThan": "1.25.2",
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"status": "affected",
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"version": "1.22.0",
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"versionType": "semver"
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}
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]
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}
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],
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"credits": [
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{
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"lang": "en",
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"type": "finder",
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"value": "Qifan Zhang (Palo Alto Networks)"
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},
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{
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"lang": "en",
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"value": "Xuanchao Xie (University of Science and Technology of China)",
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"type": "finder"
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},
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{
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"lang": "en",
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"value": "Lutong Chen (University of Science and Technology of China)",
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"type": "finder"
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},
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{
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"lang": "en",
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"value": "Kaiping Xue (University of Science and Technology of China)",
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"type": "finder"
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}
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],
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"datePublic": "2026-07-22T00:00:00.000Z",
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"descriptions": [
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{
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"lang": "en",
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"value": "In NLnet Labs Unbound 1.22.0 up to and including 1.25.1, a remote unauthenticated client can trigger a libngtcp2 assertion (if compiled with assertions on) and terminate the entire Unbound process using a single DNS-over-QUIC (DoQ) connection and one normal DNS query. This is caused by an erroneous error value passed to libngtcp2. When 'ngtcp2_conn_writev_stream()' returns 'NGTCP2_ERR_STREAM_DATA_BLOCKED', Unbound continues to call 'ngtcp2_ccerr_set_application_error()' with a '-1' error value. The 'int' literal '-1' is implicitly converted to the function's 'uint64_t error_code' parameter as '0xFFFFFFFFFFFFFFFF'. The follow-on 'ngtcp2_conn_write_connection_close()' serialises that value as a QUIC variable-length integer; because '2^64-1' exceeds the 62-bit varint ceiling, 'ngtcp2_put_uvarintlen()' fails 'assert(n < 4611686018427387904ULL)' and the whole resolver process aborts. A remote, unauthenticated DoQ client can trigger this deterministically with a single QUIC connection by advertising 'initial_max_stream_data_bidi_local = 1' in its transport parameters and sending one DoQ query without ever reading the stream."
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}
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],
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"metrics": [
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{
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"cvssV3_1": {
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"baseScore": 5.9,
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"baseSeverity": "MEDIUM",
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"vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H",
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"version": "3.1"
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},
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"format": "CVSS",
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"scenarios": [
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{
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"lang": "en",
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"value": "Unbound compiled with DoQ support ('--with-libngtcp2')"
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}
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]
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}
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],
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"problemTypes": [
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{
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"descriptions": [
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{
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"cweId": "CWE-195",
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"description": "CWE-195: Signed to Unsigned Conversion Error",
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"lang": "en",
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"type": "CWE"
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}
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]
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}
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],
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"providerMetadata": {
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"orgId": "206fc3a0-e175-490b-9eaa-a5738056c9f6",
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"shortName": "NLnet Labs",
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"dateUpdated": "2026-09-16T14:24:57.805Z"
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},
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"references": [
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{
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"tags": [
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"vendor-advisory"
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],
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"url": "https://www.nlnetlabs.nl/downloads/unbound/CVE-2026-55991.txt"
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}
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],
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"solutions": [
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{
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"lang": "en",
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"value": "This issue is fixed starting with version 1.25.2"
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}
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],
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"timeline": [
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{
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"lang": "en",
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"time": "2026-05-27T00:00:00.000Z",
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"value": "Issue reported by Qifan Zhang"
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},
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{
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"lang": "en",
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"time": "2026-06-15T00:00:00.000Z",
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"value": "NLnet Labs shares patch with Qifan Zhang"
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},
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{
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"lang": "en",
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"time": "2026-06-17T00:00:00.000Z",
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"value": "Qifan Zhang verifies patch"
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},
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{
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"lang": "en",
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"time": "2026-07-11T00:00:00.000Z",
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"value": "Issue reported by Xuanchao Xie"
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},
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{
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"lang": "en",
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"time": "2026-07-12T00:00:00.000Z",
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"value": "NLnet Labs shares patch with Xuanchao Xie"
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},
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{
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"lang": "en",
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"time": "2026-06-13T00:00:00.000Z",
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"value": "Xuanchao Xie verifies patch"
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},
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{
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"lang": "en",
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"time": "2026-07-22T00:00:00.000Z",
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"value": "Fixes released with version 1.25.2"
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}
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],
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"title": "Remote DNS-over-QUIC (DoQ) flow-control assertion failure in libngtcp2",
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"x_generator": {
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"engine": "cvelib 1.8.0"
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}
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},
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"adp": [
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{
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"metrics": [
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{
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"other": {
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"type": "ssvc",
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"content": {
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"timestamp": "2026-07-22T14:01:59.779165Z",
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"id": "CVE-2026-55991",
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"options": [
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{
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"Exploitation": "none"
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},
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{
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"Automatable": "no"
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},
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{
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"Technical Impact": "partial"
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}
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],
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"role": "CISA Coordinator",
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"version": "2.0.3"
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}
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}
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}
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],
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"title": "CISA ADP Vulnrichment",
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"providerMetadata": {
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"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
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"shortName": "CISA-ADP",
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"dateUpdated": "2026-07-22T14:03:20.789Z"
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}
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}
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]
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}
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} |