CVE-2015-5477: ISC BIND

Should you act?

Exploited: patch now if you run it

CISA has confirmed exploitation in the wild. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

Yes, if you run ISC BIND. CISA added this CVE to its Known Exploited Vulnerabilities catalog on 2026-10-08, which means there is reliable evidence of exploitation in the wild. US federal agencies must remediate by 2026-10-11; treat that as the outer limit, not the target.
EPSS 99.4%, percentile 99.9: FIRST’s model estimates a 99.4% chance of exploitation activity in the next 30 days, higher than 99.9% of all scored CVEs (very high). EPSS is a probability, not a verdict.
Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
Editorial verdict: Check exposure. BIND CVE-2015-5477: 2015 TKEY DNS Crash Bug Now in KEV — Any BIND release from the past decade is fixed, so most teams have nothing to do; the real risk is forgotten DNS servers and appliances still running pre-mid-2015 BIND, which one packet can knock offline.

What it is

named in ISC BIND 9.x before 9.9.7-P2 and 9.10.x before 9.10.2-P3 allows remote attackers to cause a denial of service (REQUIRE assertion failure and daemon exit) via TKEY queries.

CISA’s summary

ISC BIND contains a data processing errors vulnerability that could allow remote attackers to cause a denial of service via TKEY queries.

Weakness type: CWE-617, CWE-19.

Product: ISC BIND · Assigned by: mitre · Published: 2015-07-29

Affected and fixed versions

Vendor	Product	Affected versions (per CVE record)
n/a	n/a	see vendor advisory

Severity scores

Scored by	CVSS	Score	Vector
CISA-ADP	3.1	7.5 High	`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`

Attack vector: network (remotely reachable)
Attack complexity: low
Privileges required: none (no login)
User interaction: none
Scope: unchanged

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

CISA KEV: added 2026-10-08; federal due date 2026-10-11. Known ransomware use: Unknown.
CISA required action: Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
CISA SSVC assessment: exploitation active, automatable yes, technical impact total.
FIRST EPSS (model of 2026-10-21): 99.41% probability of exploitation activity in the next 30 days; percentile 99.9.

Timeline

2015-07-28 — erroneo.us brief: BIND CVE-2015-5477: 2015 TKEY DNS Crash Bug Now in KEV
2015-07-29 — CVE record published by mitre
2026-10-08 — Added to CISA’s Known Exploited Vulnerabilities catalog
2026-10-09 — CVE record last updated
2026-10-11 — CISA remediation deadline for US federal agencies

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.

Other references from the CVE record and advisory

packetstormsecurity.com packetstormsecurity.com
oracle.com oracle.com
h20564.www2.hpe.com h20564.www2.hpe.com
kb.juniper.net kb.juniper.net
security.netapp.com security.netapp.com
kb.isc.org kb.isc.org
h20566.www2.hpe.com h20566.www2.hpe.com
oracle.com oracle.com
kb.juniper.net kb.juniper.net
support.apple.com support.apple.com
1033100 securitytracker.com
kb.isc.org kb.isc.org
76092 securityfocus.com
37721 exploit-db.com
h20564.www2.hpe.com h20564.www2.hpe.com
37723 exploit-db.com
kb.isc.org kb.isc.org
kb.isc.org kb.isc.org
kc.mcafee.com kc.mcafee.com
kb.isc.org kb.isc.org

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