unbound: Unbound: Denial of Service via 'serve-expired' code path bypass

A vulnerability in Unbound's serve-expired code path allows a remote attacker to bypass pending-query limits using specially crafted DNS queries. By causing a security counter to double-decrement, the attacker can hold an arbitrary number of pending queries from a single source, resulting in a...

CVE-2026-77860

A vulnerability in Unbound's serve-expired code path allows a remote attacker to bypass pending-query limits using specially crafted DNS queries. By causing a security counter to double-decrement, the attacker can hold an arbitrary number of pending queries from a single source, resulting in a...

AZL-101718 CVE-2026-77860 affecting package unbound for versions less than 1.26.1-1

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...

DEBIAN-CVE-2026-77860

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...

CVE-2026-77860

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...

CVE-2026-77860

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...

CVE-2026-77860

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...

UBUNTU-CVE-2026-77860

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...

CVE-2026-77860

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...

CVE-2026-77860 'serve-expired' can bypass Unbound 'wait-limit'

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...

CVE-2026-77860

NLnetLabs Unbound versions 1.20.0 through 1.26.0 are affected by a double-decrement flaw in the serve-expired code path that causes the per-client wait-limit counter to be decremented twice. An attacker controlling an authoritative zone with short TTLs can alternate "slow" queries (never answered...

CVE-2026-77860 'serve-expired' can bypass Unbound 'wait-limit'

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...

EUVD-2026-80286

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...

CVE-2026-77860

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...

CVE-2026-77860: Multiple Operations on Resource in Single-Operation Context

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...

Linux Distros Unpatched Vulnerability : CVE-2026-77860

"The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available. - 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' count...

Unity Linux 20.1050e / 20.1060e / 20.1070e Security Update: unbound (UTSA-2026-104801)

The Unity Linux 20 host has a package installed that is affected by a vulnerability as referenced in the UTSA-2026-104801 advisory. In NLnet Labs Unbound 1.6.0 up to and including 1.25.1, a replay of a wildcard rrset as another piece of data, could be briefly considered DNSSEC secure based only o...

Unity Linux 20.1050e / 20.1060e / 20.1070e Security Update: unbound (UTSA-2026-104812)

The Unity Linux 20 host has a package installed that is affected by a vulnerability as referenced in the UTSA-2026-104812 advisory. In NLnet Labs Unbound 1.10.0 up to and including 1.25.1, when 'serve-expired: yes' is set together with a 'response-ip: redirect' /'response-ip-data: CNAME ' rule or...

Unity Linux 20.1050e / 20.1060e / 20.1070e Security Update: unbound (UTSA-2026-104816)

The Unity Linux 20 host has a package installed that is affected by a vulnerability as referenced in the UTSA-2026-104816 advisory. In NLnet Labs Unbound 1.20.0 up to and including 1.25.1, when Unbound is configured with 'serve-expired: yes' and 'serve-expired-client-timeout discard-timeout 0'...

CVE-2026-55717

A flaw in Unbound allows a remote attacker controlling a delegated domain to trigger a NULL pointer dereference and crash the daemon. Exploitation occurs when serve-expired: yes and specific response-ip or RPZ rules are configured, resulting in a denial of service. Mitigation Ensure serve-expired...