CVE catalog
CVE-2026-32665
In NLnet Labs Unbound 1.22.0 up to and including 1.25.1, when downstream DNS-over-QUIC (DoQ) is enabled, the first two bidirectional streams on a new QUIC connection (stream_id 0 and 4) bypass the per
- Severity
- High · CVSS 7.5
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Published
- Source
- [NVD] · [CVE record]
- EPSS
- 0.29% · Oct 25, 2026
In NLnet Labs Unbound 1.22.0 up to and including 1.25.1, when downstream DNS-over-QUIC (DoQ) is enabled, the first two bidirectional streams on a new QUIC connection (stream_id 0 and 4) bypass the per-stream 'quic-size' gate entirely, and large input buffers are allocated later, after only the 2-byte length prefix has been received from the initial streams. As a result, a remote client can make Unbound exceed the configured 'quic-size' limit with low-cost input. Using only one connection and two streams, each sending a declared 65535-byte length prefix and then holding the streams open, a client can already trivially make Unbound roughly allocate double that amount. This is a remote availability issue / memory-accounting bypass in the downstream DoQ implementation that leads to denial of service for new DoQ clients. This vulnerability needs Unbound to be compiled with DoQ support ('--with-libngtcp2') and the 'quic-port' to be configured for the listening interfaces.
Vulnerable and fixed packages
Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.
| Distribution | Package | Release | Version | Status |
|---|---|---|---|---|
| Debian | unbound | sid | 1.26.2-1 | fixed |
| Debian | unbound | forky | 1.26.2-1 | fixed |
| Debian | unbound | trixie | 1.22.0-2+deb13u3 | vulnerable |
| Debian | unbound | trixie-security | 1.26.2-0+deb13u1 | fixed |
| Debian | unbound | bookworm | 1.17.1-2+deb12u4 | vulnerable |
| Debian | unbound | bookworm-security | 1.17.1-2+deb12u3 | vulnerable |
| Ubuntu | unbound | 26.10 | 1.24.2-1ubuntu2 | vulnerable |
| Ubuntu | unbound | 26.10 | 1.25.1-1ubuntu1 | vulnerable |
| Ubuntu | unbound | 26.10 | 1.25.1-1ubuntu3 | vulnerable |
| Ubuntu | unbound | 26.04 | 1.22.0-2ubuntu2 | vulnerable |
| Ubuntu | unbound | 26.04 | 1.22.0-2ubuntu4 | vulnerable |
| Ubuntu | unbound | 26.04 | 1.24.2-1ubuntu1 | vulnerable |
| Ubuntu | unbound | 26.04 | 1.24.2-1ubuntu2 | vulnerable |
| Ubuntu | unbound | 26.04 | 1.24.2-1ubuntu2.1 | vulnerable |
| Ubuntu | unbound | 26.04 | 1.24.2-1ubuntu2.2 | vulnerable |
| Ubuntu | unbound | 26.04 | 1.24.2-1ubuntu2.3 | vulnerable |
| Ubuntu | unbound | 26.04 | 1.24.2-1ubuntu2.4 | fixed |
| Cpe | unbound | Not reported | 1.25.2 | fixed |
Fixed-version evidence
| Distribution | Package | Type | Release | Fixed version | Urgency | Origin | Bugs |
|---|---|---|---|---|---|---|---|
| Debian | unbound | source | sid | 1.25.2-1 | not yet assigned | Not reported | Not reported |
| Debian | unbound | source | forky | 1.25.2-1 | not yet assigned | Not reported | Not reported |
| Debian | unbound | source | trixie | 1.26.1-0+deb13u1 | not yet assigned | Not reported | Not reported |
| Debian | unbound | source | bookworm | (unfixed) | not yet assigned | Not reported | Not reported |
| Ubuntu | unbound | deb | 26.04 | 1.24.2-1ubuntu2.4 | Not reported | UBUNTU-CVE-2026-32665 | Not reported |
| Cpe | unbound | cpe | Not reported | 1.25.2 | Not reported | NVD-CVE-2026-32665 | Not reported |
OpenFactory catalog packages
[Debian 12 (Bookworm)]
- [libunbound8]Affected
Source package: [unbound]
Details (4)
1.17.1-2+deb12u4· amd64 · bookwormAffected
nvd · unbound · debian · bookworm; nvd · unbound · debian · 12
1.17.1-2+deb12u4· arm64 · bookwormAffected
nvd · unbound · debian · bookworm; nvd · unbound · debian · 12
1.17.1-2+deb12u3· amd64 · bookworm-securityAffected
nvd · unbound · debian · bookworm; nvd · unbound · debian · 12
1.17.1-2+deb12u3· arm64 · bookworm-securityAffected
nvd · unbound · debian · bookworm; nvd · unbound · debian · 12
- [libunbound-dev]Affected
Source package: [unbound]
Details (4)
1.17.1-2+deb12u4· amd64 · bookwormAffected
nvd · unbound · debian · bookworm; nvd · unbound · debian · 12
1.17.1-2+deb12u4· arm64 · bookwormAffected
nvd · unbound · debian · bookworm; nvd · unbound · debian · 12
1.17.1-2+deb12u3· amd64 · bookworm-securityAffected
nvd · unbound · debian · bookworm; nvd · unbound · debian · 12
1.17.1-2+deb12u3· arm64 · bookworm-securityAffected
nvd · unbound · debian · bookworm; nvd · unbound · debian · 12
- [python3-unbound]Affected
Source package: [unbound]
Details (4)
1.17.1-2+deb12u4· amd64 · bookwormAffected
nvd · unbound · debian · bookworm; nvd · unbound · debian · 12
1.17.1-2+deb12u4· arm64 · bookwormAffected
nvd · unbound · debian · bookworm; nvd · unbound · debian · 12
1.17.1-2+deb12u3· amd64 · bookworm-securityAffected
nvd · unbound · debian · bookworm; nvd · unbound · debian · 12
1.17.1-2+deb12u3· arm64 · bookworm-securityAffected
nvd · unbound · debian · bookworm; nvd · unbound · debian · 12
- [unbound]Affected
Details (4)
1.17.1-2+deb12u4· amd64 · bookwormAffected
nvd · unbound · debian · bookworm; nvd · unbound · debian · 12
1.17.1-2+deb12u4· arm64 · bookwormAffected
nvd · unbound · debian · bookworm; nvd · unbound · debian · 12
1.17.1-2+deb12u3· amd64 · bookworm-securityAffected
nvd · unbound · debian · bookworm; nvd · unbound · debian · 12
1.17.1-2+deb12u3· arm64 · bookworm-securityAffected
nvd · unbound · debian · bookworm; nvd · unbound · debian · 12
- [unbound-anchor]Affected
Source package: [unbound]
Details (4)
1.17.1-2+deb12u4· amd64 · bookwormAffected
nvd · unbound · debian · bookworm; nvd · unbound · debian · 12
1.17.1-2+deb12u4· arm64 · bookwormAffected
nvd · unbound · debian · bookworm; nvd · unbound · debian · 12
1.17.1-2+deb12u3· amd64 · bookworm-securityAffected
nvd · unbound · debian · bookworm; nvd · unbound · debian · 12
1.17.1-2+deb12u3· arm64 · bookworm-securityAffected
nvd · unbound · debian · bookworm; nvd · unbound · debian · 12
- [unbound-host]Affected
Source package: [unbound]
Details (4)
1.17.1-2+deb12u4· amd64 · bookwormAffected
nvd · unbound · debian · bookworm; nvd · unbound · debian · 12
1.17.1-2+deb12u4· arm64 · bookwormAffected
nvd · unbound · debian · bookworm; nvd · unbound · debian · 12
1.17.1-2+deb12u3· amd64 · bookworm-securityAffected
nvd · unbound · debian · bookworm; nvd · unbound · debian · 12
1.17.1-2+deb12u3· arm64 · bookworm-securityAffected
nvd · unbound · debian · bookworm; nvd · unbound · debian · 12
[Debian 13 (Trixie)]
- [libunbound8]Affected
Source package: [unbound]
Details (6)
1.22.0-2+deb13u3· amd64 · trixieAffected · Fixed:
1.26.1-0+deb13u1nvd · unbound · debian · 13
1.22.0-2+deb13u3· arm64 · trixieAffected · Fixed:
1.26.1-0+deb13u1nvd · unbound · debian · 13
1.22.0-2+deb13u3· amd64 · trixie-security · Historical versionAffected · Fixed:
1.26.1-0+deb13u1nvd · unbound · debian · 13
1.22.0-2+deb13u3· arm64 · trixie-securityAffected · Fixed:
1.26.1-0+deb13u1nvd · unbound · debian · 13
1.26.1-0+deb13u1· amd64 · trixie-security · Historical versionFixed · Fixed:
1.26.1-0+deb13u1nvd · unbound · debian · 13
1.26.2-0+deb13u1· amd64 · trixie-securityFixed · Fixed:
1.26.1-0+deb13u1nvd · unbound · debian · 13
- [libunbound-dev]Affected
Source package: [unbound]
Details (6)
1.22.0-2+deb13u3· amd64 · trixieAffected · Fixed:
1.26.1-0+deb13u1nvd · unbound · debian · 13
1.22.0-2+deb13u3· arm64 · trixieAffected · Fixed:
1.26.1-0+deb13u1nvd · unbound · debian · 13
1.22.0-2+deb13u3· amd64 · trixie-security · Historical versionAffected · Fixed:
1.26.1-0+deb13u1nvd · unbound · debian · 13
1.22.0-2+deb13u3· arm64 · trixie-securityAffected · Fixed:
1.26.1-0+deb13u1nvd · unbound · debian · 13
1.26.1-0+deb13u1· amd64 · trixie-security · Historical versionFixed · Fixed:
1.26.1-0+deb13u1nvd · unbound · debian · 13
1.26.2-0+deb13u1· amd64 · trixie-securityFixed · Fixed:
1.26.1-0+deb13u1nvd · unbound · debian · 13
- [python3-unbound]Affected
Source package: [unbound]
Details (6)
1.22.0-2+deb13u3· amd64 · trixieAffected · Fixed:
1.26.1-0+deb13u1nvd · unbound · debian · 13
1.22.0-2+deb13u3· arm64 · trixieAffected · Fixed:
1.26.1-0+deb13u1nvd · unbound · debian · 13
1.22.0-2+deb13u3· amd64 · trixie-security · Historical versionAffected · Fixed:
1.26.1-0+deb13u1nvd · unbound · debian · 13
1.22.0-2+deb13u3· arm64 · trixie-securityAffected · Fixed:
1.26.1-0+deb13u1nvd · unbound · debian · 13
1.26.1-0+deb13u1· amd64 · trixie-security · Historical versionFixed · Fixed:
1.26.1-0+deb13u1nvd · unbound · debian · 13
1.26.2-0+deb13u1· amd64 · trixie-securityFixed · Fixed:
1.26.1-0+deb13u1nvd · unbound · debian · 13
- [unbound]Affected
Details (6)
1.22.0-2+deb13u3· amd64 · trixieAffected · Fixed:
1.26.1-0+deb13u1nvd · unbound · debian · 13
1.22.0-2+deb13u3· arm64 · trixieAffected · Fixed:
1.26.1-0+deb13u1nvd · unbound · debian · 13
1.22.0-2+deb13u3· amd64 · trixie-security · Historical versionAffected · Fixed:
1.26.1-0+deb13u1nvd · unbound · debian · 13
1.22.0-2+deb13u3· arm64 · trixie-securityAffected · Fixed:
1.26.1-0+deb13u1nvd · unbound · debian · 13
1.26.1-0+deb13u1· amd64 · trixie-security · Historical versionFixed · Fixed:
1.26.1-0+deb13u1nvd · unbound · debian · 13
1.26.2-0+deb13u1· amd64 · trixie-securityFixed · Fixed:
1.26.1-0+deb13u1nvd · unbound · debian · 13
- [unbound-anchor]Affected
Source package: [unbound]
Details (6)
1.22.0-2+deb13u3· amd64 · trixieAffected · Fixed:
1.26.1-0+deb13u1nvd · unbound · debian · 13
1.22.0-2+deb13u3· arm64 · trixieAffected · Fixed:
1.26.1-0+deb13u1nvd · unbound · debian · 13
1.22.0-2+deb13u3· amd64 · trixie-security · Historical versionAffected · Fixed:
1.26.1-0+deb13u1nvd · unbound · debian · 13
1.22.0-2+deb13u3· arm64 · trixie-securityAffected · Fixed:
1.26.1-0+deb13u1nvd · unbound · debian · 13
1.26.1-0+deb13u1· amd64 · trixie-security · Historical versionFixed · Fixed:
1.26.1-0+deb13u1nvd · unbound · debian · 13
1.26.2-0+deb13u1· amd64 · trixie-securityFixed · Fixed:
1.26.1-0+deb13u1nvd · unbound · debian · 13
- [unbound-host]Affected
Source package: [unbound]
Details (6)
1.22.0-2+deb13u3· amd64 · trixieAffected · Fixed:
1.26.1-0+deb13u1nvd · unbound · debian · 13
1.22.0-2+deb13u3· arm64 · trixieAffected · Fixed:
1.26.1-0+deb13u1nvd · unbound · debian · 13
1.22.0-2+deb13u3· amd64 · trixie-security · Historical versionAffected · Fixed:
1.26.1-0+deb13u1nvd · unbound · debian · 13
1.22.0-2+deb13u3· arm64 · trixie-securityAffected · Fixed:
1.26.1-0+deb13u1nvd · unbound · debian · 13
1.26.1-0+deb13u1· amd64 · trixie-security · Historical versionFixed · Fixed:
1.26.1-0+deb13u1nvd · unbound · debian · 13
1.26.2-0+deb13u1· amd64 · trixie-securityFixed · Fixed:
1.26.1-0+deb13u1nvd · unbound · debian · 13
Observed:
References
- [https://ftp.suse.com/pub/projects/security/csaf/opensuse-su-2026_11380-1.json]
- [https://nvd.nist.gov/vuln/detail/CVE-2026-32665]
- [https://osv.dev/vulnerability/DEBIAN-CVE-2026-32665]
- [https://osv.dev/vulnerability/UBUNTU-CVE-2026-32665]
- [https://security-tracker.debian.org/tracker/CVE-2026-32665]
- [https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-32665.json]
- [https://wid.cert-bund.de/.well-known/csaf/white/2026/wid-sec-w-2026-3038.json]
- [https://www.nlnetlabs.nl/downloads/unbound/CVE-2026-32665.txt]
[CERT-Bund public advisories] · [Debian Security Tracker] · [FIRST EPSS] · [National Vulnerability Database (NVD)] · [OSV Package Vulnerability Database] · [Red Hat security advisories and VEX] · [SUSE security advisories and VEX]