OPENSUSE-SU-2026:21550-1: unbound security update

OPENSUSE-SU-2026:21550-1, released August 10, 2026, fixes 24 CVEs in unbound (version 1.25.2-160000.1.1). None of them is reported as exploited. Patch Radar priority: High.

High

CVEs closed

None rated Critical

Exploited

None reported

Highest CVSS

9.3

Base score, 0 to 10

Highest EPSS

0.0046

40th percentile

Priority of the 24 CVEs

Patch now 0
                                Urgent 0
                                High 6
                                Routine 18

Fixed package versions

Product	Release	Fixed in
unbound	opensuse-leap 16.0	1.25.2-160000.1.1

CVEs this fix closes

Priority	CVE	Title	CVSS	EPSS	Exploitation
High	CVE-2026-40691	Packet of death for DNSCrypt over TCP	7.5	0.0029	None reported
High	CVE-2026-32665	Remote DNS-over-QUIC denial of service due to `quic-size` budget bypass	7.5	0.0029	None reported
High	CVE-2026-55973	'dns-error-reporting: yes' leads to stack buffer overflow	8.6	0.0028	None reported
High	CVE-2026-50252	Possible cache poisoning attack by mapping source port population per thread	9.3	0.0017	None reported
High	CVE-2026-44690	Cross-zone wildcard cache poisoning via RRSIG.labels manipulation	8.6	0.0015	None reported
High	CVE-2026-40622	Another 'ghost domain names' attack variant	7.5	0.0014	None reported
Routine	CVE-2026-50045	'max-global-quota' reset by DNSSEC validation restarts	5.3	0.0046	None reported
Routine	CVE-2026-41637	Degradation of resolution service from improperly accounted client-terminated DNS-over-QUIC queries	3.7	0.0037	None reported
Routine	CVE-2026-14586	Assertion in libngtcp2 when under pressure in high concurrency DNS-over-QUIC environments	5.9	0.0037	None reported
Routine	CVE-2026-55991	Remote DNS-over-QUIC (DoQ) flow-control assertion failure in libngtcp2	5.9	0.0037	None reported
Routine	CVE-2026-56444	Degradation of resolution service when 'discard-timeout' and 'serve-expired-client-timeout' are combined in unusual configuration	5.9	0.0037	None reported
Routine	CVE-2026-50251	Attacker supplied '0.0.0.0'/'::' glue triggers defensive full-cache flush	5.3	0.0025	None reported
Routine	CVE-2026-44621	Libunbound applications configured with 'unwanted-reply-threshold' could eventually be abruptly terminated	5.9	0.0025	None reported
Routine	CVE-2026-55990	Packet of death for a DNSCrypt misconfigured Unbound	5.9	0.0025	None reported
Routine	CVE-2026-54478	DNS Cookie bypass when combined with proxy-protocol use	3.7	0.0024	None reported
Routine	CVE-2026-50046	Possible heap use-after-free in an error path when a DoT forwarded query is jostled out	5.9	0.0024	None reported
Routine	CVE-2026-55717	'serve-expired-client-timeout' and 'response-ip' CNAME redirect could lead to a crash	5.9	0.0024	None reported
Routine	CVE-2026-44687	Off-by-one error in 'harden-below-nxdomain' logic can shadow a stub/forward zone by a legitimate parent's NXDOMAIN	3.7	0.0022	None reported
Routine	CVE-2026-42955	Extra fix for CVE-2026-40622 to also clamp the TTL of A/AAAA records disallowing a one-time 'ghost domain' delegation renewal via glue records	3.7	0.0020	None reported
Routine	CVE-2026-46582	A wildcard replay, as another piece of data, triggers poisoning in the serve expired reply path	3.7	0.0019	None reported
Routine	CVE-2026-55708	Privacy/configuration issue when adding local data in views through 'unbound-control'	3.1	0.0016	None reported
Routine	CVE-2026-50248	BOGUS configured primary hostname accepted for XFR in auth/rpz zones	6.5	0.0013	None reported
Routine	CVE-2026-56416	Possible heap buffer overflow when validator canonicalizes RDATA that contains domain name	4.8	0.0012	None reported
Routine	CVE-2026-50243	'response-ip'/'rpz' can rewrite BOGUS answers instead of returning SERVFAIL	3.7	0.0011	None reported

Also fixes CVE-2026-40691

libunbound2 1.6.7-1ubuntu2.6+esm6
libunbound2 on Ubuntu 18.04.6 LTS (bionic)
python-unbound 1.6.7-1ubuntu2.6+esm6
python-unbound on Ubuntu 18.04.6 LTS (bionic)
python3-unbound 1.6.7-1ubuntu2.6+esm6
python3-unbound on Ubuntu 18.04.6 LTS (bionic)
unbound 1.6.7-1ubuntu2.6+esm6
unbound on Ubuntu 18.04.6 LTS (bionic)
unbound-anchor 1.6.7-1ubuntu2.6+esm6
unbound-anchor on Ubuntu 18.04.6 LTS (bionic)
unbound-host 1.6.7-1ubuntu2.6+esm6
unbound-host on Ubuntu 18.04.6 LTS (bionic)
libunbound8 1.24.2-1ubuntu2.4
libunbound8 on Ubuntu 26.04.1 LTS (resolute)
python3-unbound 1.24.2-1ubuntu2.4
python3-unbound on Ubuntu 26.04.1 LTS (resolute)

Vendor advisory

https://osv.dev/vulnerability/openSUSE-SU-2026:21550-1

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