Security Vulnerabilities
Novel vulnerabilities to launch algorithmic complexity attacks on DNSSEC have been researched under the term 'ReTrap'. These result in degradation of service when malicious zones are used to serve the algorithmic complexity vulnerabilities. NLnet Labs Unbound up to and including 1.26.0 is vulnerable to some of them. TagTrap, where the triple(Zone, Algo, KeyTag) matching mechanism introduces a significant attack vector when resolvers handle malicious responses containing numerous mismatched DNSKEY, RRSIG, and DS record. DelegationTrap, where constructing the chain-of-trust requires iterative validation of DNSKEY and DS records from the root zone downward. For deeply nested domains, this results in significant computational overhead. NsecTrap, where responses with excessive invalid NSEC records compel the resolver to validate each one. AdditionalTrap, where Unbound by default would try to DNSSEC validate the ADDITIONAL section as well. This can be exploited to waste validation resources by malicious users.
CVSS Score
5.3
EPSS Score
0.005
Published
2026-09-16
In NLnetLabs Unbound 1.20.0 up to and including 1.26.0, a vulnerability on the 'serve-expired' code path can cause a double decrement on the 'wait-limit' counter per client IP essentially bypassing one of the counter measures that was introduced for DNSBomb (CVE-2024-33655). A malicious actor can exploit this by controlling an authoritative zone with short TTL, so cached entries expire quickly. Each 'slow' query, one the attacker's authoritative never answers, is followed by one query for an expired cached name, which is answered immediately via the 'serve-expired' path and decrements the counter twice. This second query was named 'pump'. By alternating slow queries and pumps, the attacker keeps the per-client counter at or below the configured 'wait-limit' indefinitely, and can hold an arbitrary number of pending queries from a single source IP, up to the global mesh quota (num-queries-per-thread); eventually bypassing one of the counter measures introduced for DNSBomb (CVE-2024-33655). This vulnerability is present on the 'serve-expired' code path.
CVSS Score
3.7
EPSS Score
0.003
Published
2026-09-16
In NLnet Labs Unbound 1.13.2 up to and including 1.26.1, a vulnerability in ZONEMD configured zones (zonemd-check: yes) which are located below (but not at) a trust anchor allow for an attack window where (tampered with) zone contents are served (or stored to disk) prior to the ZONEMD integrity check. This is caused by the needed DS/DNSKEY asynchronous resolution that needs to happen before the ZONEMD check completes. If a zonefile is written to disk (zonefile: option) while the ZONEMD check failed, the tampered data are reloaded on startup and available until ZONEMD verification concludes again. If verification fails, the data is not served any more but still persists on disk for future reloads.
CVSS Score
4.4
EPSS Score
0.002
Published
2026-09-16
NLnet Labs Unbound 1.22.0 up to and including 1.26.1, has a use-after-free vulnerability when compiled for DNS-over-QUIC support with '--with-libngtcp2'. Each DoQ stream owns an output buffer that holds the DNS response. ngtcp2's retransmission buffer keeps a shallow pointer into the output buffer for as long as a STREAM frame may be resent. On a client RESET_STREAM, the output buffer is freed but ngtcp2 still holds the matching retransmission entries. The next PTO timeout makes ngtcp2 re-encode the STREAM frame and copy from the freed buffer. A malicious actor that can query Unbound over DoQ and that withholds ACKs, sends RESET_STREAM, and waits for PTO, reaches this use-after-free with no privilege. This leads to retransmissions against freed memory and eventually an abnormal server exit under a 20-query spray.
CVSS Score
6.5
EPSS Score
0.003
Published
2026-09-16
Use after free in Microsoft Edge (Chromium-based) allows an unauthorized attacker to elevate privileges over a network.
CVSS Score
8.8
EPSS Score
0.008
Published
2026-09-15
Heap-based buffer overflow in Microsoft Edge (Chromium-based) allows an unauthorized attacker to execute code over a network.
CVSS Score
8.8
EPSS Score
0.008
Published
2026-09-15
Race condition in Core in Google Chrome prior to 153.0.8010.47 allowed a remote attacker who had compromised the renderer process to potentially execute arbitrary code outside the sandbox via a crafted HTML page. (Chromium security severity: High)
CVSS Score
8.3
EPSS Score
0.003
Published
2026-09-15
Race condition in PlatformIntegration in Google Chrome on on Mac prior to 153.0.8010.47 allowed a remote attacker who had compromised the renderer process and leveraged social engineering to obtain sensitive information via a crafted HTML page. (Chromium security severity: High)
CVSS Score
5.3
EPSS Score
0.002
Published
2026-09-15
Use after free in V8 in Google Chrome prior to 153.0.8010.47 allowed a remote attacker to execute arbitrary code inside the sandbox via a crafted HTML page. (Chromium security severity: High)
CVSS Score
8.8
EPSS Score
0.003
Published
2026-09-15
Integer overflow in Compositing in Google Chrome prior to 153.0.8010.47 allowed a remote attacker to obtain cross-origin data via a crafted HTML page. (Chromium security severity: High)
CVSS Score
4.3
EPSS Score
0.002
Published
2026-09-15