How severe is CVE-2026-5950?

CVE-2026-5950 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability low.

Is CVE-2026-5950 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (42nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-5950?

CVE-2026-5950 affects Isc Bind. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-5950?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-5950 have an EU (EUVD) identifier?

Yes. CVE-2026-5950 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-31109.

When was CVE-2026-5950 published?

CVE-2026-5950 was published on 2026-05-20 and last updated on 2026-06-17.

CVE-2026-5950

CVE-2026-5950 is a medium-severity vulnerability in Isc Bind with a CVSS 3.x base score of 5.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-606.

Key facts

Severity: Medium (CVSS 3.x base score 5.3)
EPSS exploit prediction: 1% (42nd percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-31109
Weakness: CWE-606
Affected product: Isc Bind
Published: 2026-05-20
Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is CVE-2026-5950?: 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.
How severe is CVE-2026-5950?: CVE-2026-5950 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability low.
Is CVE-2026-5950 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (42nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-5950?: CVE-2026-5950 affects Isc Bind. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-5950?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-5950 have an EU (EUVD) identifier?: Yes. CVE-2026-5950 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-31109.
When was CVE-2026-5950 published?: CVE-2026-5950 was published on 2026-05-20 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:isc:bind:*:*:*:*:-:*:*:*

More vulnerabilities in Isc Bind

CVE-2008-0122 — Critical (CVSS 10.0): Off-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…
CVE-2001-0011 — Critical (CVSS 10.0): Buffer overflow in nslookupComplain function in BIND 4 allows remote attackers to gain root privileges.
CVE-2001-0013 — Critical (CVSS 10.0): Format string vulnerability in nslookupComplain function in BIND 4 allows remote attackers to gain root privileges.
CVE-2001-0010 — Critical (CVSS 10.0): Buffer overflow in transaction signature (TSIG) handling code in BIND 8 allows remote attackers to gain root privileges.
CVE-2000-1029 — Critical (CVSS 10.0): Buffer overflow in host command allows a remote attacker to execute arbitrary commands via a long response to an AXFR…
CVE-1999-0837 — Critical (CVSS 10.0): Denial of service in BIND by improperly closing TCP sessions via so_linger.

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