Vulnerability record · CVE-2026-5950 · published 20 May 2026

CVE-2026-5950: Isc bind vulnerability

Isc · Bind

An unbounded resend loop vulnerability exists in the BIND 9 resolver state machine during bad-server handling, enabling a remote unauthenticated attacker to cause severe resource exhaustion by sending queries that trigger specific retry conditions. This issue affects BIND 9 versions 9.18.36 through 9.18.48, 9.20.8 through 9.20.22, 9.21.7 through 9.21.21, 9.18.36-S1 through 9.18.48-S1, and 9.20.9-S1 through 9.20.22-S1.

5.3 CVSS 3.1 Medium EPSS 0.80% · top 45.2% CWE-606 · CWE-606

5.3CVSS 3.1 base score

0.80%EPSS exploitation probability, 30 days

NoNot in CISA KEV

1Affected product versions listed by NVD

4References

23 Jul 2026Last modified by NVD

Description

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

Bind Isc

References

Link	Tags
https://downloads.isc.org/isc/bind9/9.18.49	Patch
https://downloads.isc.org/isc/bind9/9.20.23	Patch
https://downloads.isc.org/isc/bind9/9.21.22	Patch
https://kb.isc.org/docs/cve-2026-5950	Vendor Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

10.0CVE-2008-0122Isc bind vulnerabilityOff-by-one error in the inet_network function in libbind in ISC BIND 9.4.2 and earlier, as used in libc in FreeBSD 6.2 through 7.0-PRERELEASE, allows…EPSS 12%16 Jan 2008 10.0CVE-2001-0010Isc bind vulnerabilityBuffer overflow in transaction signature (TSIG) handling code in BIND 8 allows remote attackers to gain root privileges.EPSS 32%12 Feb 2001 10.0CVE-2001-0011Isc bind vulnerabilityBuffer overflow in nslookupComplain function in BIND 4 allows remote attackers to gain root privileges.EPSS 7.7%12 Feb 2001 10.0CVE-2001-0013Isc bind vulnerabilityFormat string vulnerability in nslookupComplain function in BIND 4 allows remote attackers to gain root privileges.EPSS 11%12 Feb 2001 10.0CVE-2000-1029Isc bind vulnerabilityBuffer overflow in host command allows a remote attacker to execute arbitrary commands via a long response to an AXFR query.EPSS 14%11 Dec 2000 10.0CVE-1999-0837Isc bind vulnerabilityDenial of service in BIND by improperly closing TCP sessions via so_linger.EPSS 2.7%10 Nov 1999 10.0CVE-1999-0009Data general dg ux vulnerabilityInverse query buffer overflow in BIND 4.9 and BIND 8 Releases.EPSS 29%8 Apr 1998 9.8CVE-2026-3593Isc bind use after free vulnerabilityA use-after-free vulnerability exists within the DNS-over-HTTPS implementation. This issue affects BIND 9 versions 9.20.0 through 9.20.22, 9.21.0 thr…EPSS 1.1%20 May 2026

Source: NIST National Vulnerability Database (record CVE-2026-5950), CISA KEV, FIRST EPSS (scores of 2026-09-29). This page is refreshed as NVD updates the record.