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Used in attacks· fix by 2026-10-117.5High

ISC BIND

CVE-2015-5477

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

What this means for your business

  • It affects ISC BIND. It matters if your company, or a supplier that handles your data, runs it.
  • Attackers are already using it. CISA added it to its list of flaws used in real attacks on 8 October 2026.
  • An attacker can use it remotely, over a network, without a login, and without anyone at your company clicking anything.
  • FIRST's prediction model gives it a 99% chance of attack attempts being seen in the next 30 days, ranking above 99% of all known flaws.

What to do

  1. 1Check whether your company or your suppliers run ISC BIND, and which version. The affected versions are listed further down this page.
  2. 2If you do, apply the vendor's fix. A patch or vendor advisory has been published.
  3. 3Treat it as urgent. US federal agencies must fix it by 11 October 2026. That deadline does not apply to private companies, but it shows how seriously CISA takes it.
  4. 4Because attackers have used it, check the affected systems for signs of a break-in, not only for the update.

Fastnexa security experts

Attackers are already using this flaw. Is your ISC BIND exposed?

Tell us where you run ISC BIND and a Fastnexa penetration tester will check whether this flaw, or others like it, can be used against your websites, apps and network.

The full test is free for our first 10 founding clients until 31 December 2026. See the offer

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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’s wording, unedited. The notes it mentions are in CISA’s catalogue entry.

Scoring

CVSS
7.5 (v3.1)
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness
CWE-19
Assigned by
cve@mitre.org

Dates

Published
2026-10-08
Last modified
2026-10-09
Added to KEV
2026-10-08
Remediation due
2026-10-11
Sources
CISA KEV, NVD

Affected products

  • Juniper Junos- 12.1, 13.1 - 13.2, 12.1, 12.1r, 12.1x44, 12.1x45, 12.1x46, 12.1x47, 12.3, 12.3x48, 12.3x50, 13.2, 13.2x51, 14.1, 14.1x50, 14.1x51, 14.1x53, 14.2, 15.1, 15.1x49, 15.1x53
  • Juniper J2300all versions
  • Juniper J2320all versions
  • Juniper J2350all versions
  • Juniper J4300all versions
  • Juniper J4350all versions
  • Juniper J4350 Nebsall versions
  • Juniper J6300all versions
  • Juniper J635 Nebsall versions
  • Juniper J6350all versions
  • Juniper Jx-4briall versions
  • Juniper Jx-4ct1e1all versions

As listed in the NVD configuration data. Not a statement about your estate.

References