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CVE-2015-5477

From Exploited flaws, HARD’s guide to the flaws being used in attacks · Checked
This article is about a flaw in ISC BIND. For every flaw being used in attacks, see Exploited flaws.

CVE-2015-5477 is a security flaw in ISC BIND. Attackers can crash ISC BIND or stop it working. The US Cybersecurity and Infrastructure Security Agency (CISA) added it to its catalog of flaws known to be used in attacks on 8 Oct 2026.[1]

ISC BIND is business software or equipment. Most families won’t have it, but attackers break into it to get inside companies, and from there to what those companies hold about their customers, patients and staff. ISC has published a fix or advice.

Description

CISA calls it a data processing errors in ISC BIND. In its words: “ISC BIND contains a data processing errors vulnerability that could allow remote attackers to cause a denial of service via TKEY queries.”[1]

The CVE record adds: “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.”[2]

The underlying weakness is CWE-19, in MITRE’s list of common software weaknesses.

It scores 7.5 out of 10 on the Common Vulnerability Scoring System, which rates it high, scored by the organisation that published the CVE using CVSS 3.1.[2]

Affected versions

NVD’s record doesn’t list version ranges for it; ISC’s advisory has them[3]. CISA names the product as ISC BIND.

Most families won’t have ISC BIND; it’s for whoever looks after IT at work.

Exploitation

CISA added it to its catalog of known exploited vulnerabilities on 8 Oct 2026, 4,089 days after it was made public. CISA lists a flaw only when it has reliable evidence of it being exploited, and gave US federal agencies until 11 Oct 2026 to fix it.[1]

FIRST’s Exploit Prediction Scoring System, which estimates how likely a flaw is to be used in attacks in the next 30 days from what it sees across the internet, puts it at over 99%. That’s in the top 1% of the flaws it scores.[4]

CISA assesses it as automatable: attackers can run it against many targets at once.

CISA doesn’t say who was attacked, or how.

Fix

ISC has published a fix or advice.[3] CISA’s 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).”[1]

  1. Check whether you use it.ISC BIND is business software or equipment, so most families won’t have it. If you run a business, or work from home on company equipment, ask whoever looks after your IT.
  2. Send this page to your IT person.Ask them to confirm it’s fixed, or not in use. CISA gave US government agencies until 11 Oct 2026 to fix it.
  3. If it can’t be fixed, take it offline.CISA’s advice when there’s no fix is to stop using the product, or take it off the internet, until there is one.

You can’t fix someone else’s server, but you can watch for what follows a break-in like this: a breach notice, a password reset you didn’t ask for, or a scam message that knows things it shouldn’t. HARD watches for those for you and your family.

Timeline

DateEvent
The flaw is made public in the National Vulnerability Database, with a severity score of 7.5.[2]
CISA adds it to its catalog of flaws known to be used in attacks.[1]
CISA’s deadline for US government agencies to fix it.[1]
FIRST puts the odds of it being used in attacks in the next 30 days at over 99%.[4]

See also

Similar flaws

  • CVE-2015-1671, Microsoft Windows: remote code execution ·
  • CVE-2015-1770, Microsoft Office: uninitialized memory use ·

Added the same day

  • CVE-2023-22894, Strapi: cleartext storage of sensitive information ·
  • CVE-2021-3199, ONLYOFFICE Docs: server path traversal ·
  • CVE-2016-3081, Apache Struts: command injection ·
  • CVE-2015-3306, ProFTPD: improper access control ·

References

  1. ^ Cybersecurity and Infrastructure Security Agency. “ISC BIND Data Processing Errors Vulnerability”. Known Exploited Vulnerabilities Catalog, added 8 Oct 2026.
  2. ^ National Institute of Standards and Technology. “CVE-2015-5477 Detail”. National Vulnerability Database, published 29 Jul 2015.
  3. ^ ISC. Advisories and fixes: web.archive.org, access.redhat.com, supportportal.juniper.net.
  4. ^ FIRST. “Exploit Prediction Scoring System”. EPSS 0.996, percentile 99.9, 31 Oct 2026.
  5. CVE Program. “CVE-2015-5477”. The official CVE record.

This article is built from CISA’s catalog (version 2026.10.30), NVD’s record and FIRST’s scores, kept in HARD’s database and checked every morning. The plain English is HARD’s.