TI-2026-05217 Aliases CVE-2026-5950 GHSA-2pjm-rchf-gxmp

Unbounded resend loop in BIND 9 resolver

LOW 31CWE-606Published 2026-05-20 · Updated 2026-05-20

Key facts

Attack vector: Network
Privileges required: None
User interaction: None
Attack complexity: Low
Impact type: —
Confidentiality · integrity · availability: None · None · Low
Fix status: Partial Red Hat: 1 fixed, 6 without a fix

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.0066 51st percentileScored 2026-11-07

Fix Partial Red Hat: 1 advisoryRed Hat: 1 fixed, 6 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: None
Automatable: Yes
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
ISC	BIND 9	9.18.36 – 9.18.48; 9.20.8 – 9.20.22; 9.21.7 – 9.21.21; 9.18.36-S1 – 9.18.48-S1; 9.20.9-S1 – 9.20.22-S1	—	No fix listed	CNA

BIND 9 VendorISC Affected 9.18.36 – 9.18.48; 9.20.8 – 9.20.22; 9.21.7 – 9.21.21; 9.18.36-S1 – 9.18.48-S1; 9.20.9-S1 – 9.20.22-S1 Fixed in — No fix listed CNA

CPE configurations NVD · 1

CPE	Versions	Role	Vendor
cpe:2.3:a:isc:bind:::::-:::*	9.18.36 to before 9.18.49; 9.20.8 to before 9.20.23; 9.21.7 to before 9.21.21	Vulnerable	ISC

cpe:2.3:a:isc:bind:*:*:*:*:-:*:*:* Versions 9.18.36 to before 9.18.49; 9.20.8 to before 9.20.23; 9.21.7 to before 9.21.21 Vulnerable ·ISC

Remediation

Red Hat 1 advisory

RHSA-2026:20334 Released 2026-05-21 · Red Hat rating Important
Red Hat Hardened Images RPMs bug fix and enhancement update
- Red Hat Hardened Images bind-9.18.49-1.hum1@aarch64, bind-9.18.49-1.hum1@src, bind-9.18.49-1.hum1@x86_64 +12

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

Product	Status	Plan or fix
Red Hat Enterprise Linux 10	Affected	No fix yet
Red Hat Enterprise Linux 6	Affected	No fix yet: Fix deferred
Red Hat Enterprise Linux 7	Affected	No fix yet: Fix deferred
Red Hat Enterprise Linux 8	Affected	No fix yet: Fix deferred
Red Hat Enterprise Linux 9	Affected	No fix yet: Fix deferred
Red Hat OpenShift Container Platform 4	Affected	No fix yet: Fix deferred
Red Hat Hardened Images	Fixed	RHSA-2026:20334

Timeline

2026-10-02 Threatist record created from CVE-2026-5950
2026-10-03 Alias added: GHSA-2pjm-rchf-gxmp

References

Patch 3

Advisory 1

CVE-2026-5950

TI-2015-04610 Assertion failure in ISC BIND named via TKEY queries KEVCVSS 3.1HIGH 7.5
TI-2023-27571 Certain DNSSEC aspects of the DNS protocol (in RFC 4033, 4034, 4035, 6840, and related… CVSS 3.1HIGH 7.5
TI-2021-07476 A second vulnerability in BIND's GSSAPI security policy negotiation can be targeted by a buffer overflow attack CVSS 3.1CRITICAL 9.8
TI-2023-27773 The Closest Encloser Proof aspect of the DNS protocol (in RFC 5155 when RFC 9276 guidance… CVSS 3.1HIGH 7.5
TI-2020-06910 A logic error in code which checks TSIG validity can be used to trigger an assertion failure in tsig.c CVSS 3.1HIGH 7.5
TI-2016-02320 buffer.c in named in ISC BIND 9 before 9.9.9-P3, 9.10.x before 9.10.4-P3, and 9.11.x… CVSS 3.0HIGH 7.5

See all 192 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences