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CVE-2023-27532

From Exploited flaws, HARD’s guide to the flaws being used in attacks · Checked
This article is about a flaw in Veeam Backup & Replication. For every flaw being used in attacks, see Exploited flaws; for Veeam’s, see Veeam flaws being used in attacks.

CVE-2023-27532 is a security flaw in Veeam Backup & Replication, backup software companies use. Attackers can get into Veeam Backup & Replication without a valid password. The US Cybersecurity and Infrastructure Security Agency (CISA) added it to its catalog of flaws known to be used in attacks on 22 Aug 2023, and says ransomware gangs have used it.[1]

Veeam Backup & Replication 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. Veeam has published a fix or advice.

Description

CISA calls it a cloud connect missing authentication for critical function in Veeam Backup & Replication. In its words: “Veeam Backup & Replication Cloud Connect component contains a missing authentication for critical function vulnerability that allows an unauthenticated user operating within the backup infrastructure network perimeter to obtain encrypted credentials stored in the configuration database. This may lead to an attacker gaining access to the backup infrastructure hosts.”[1]

The underlying weakness is missing authentication (CWE-306), in MITRE’s list of common software weaknesses.[2]

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

Affected versions

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

Most families won’t have Veeam Backup & Replication; it’s for whoever looks after IT at work.

Exploitation

CISA added it to its catalog of known exploited vulnerabilities on 22 Aug 2023, 165 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 12 Sep 2023 to fix it.[1] CISA says ransomware gangs have used it.

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 81%. 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

Veeam has published a fix or advice.[3] CISA’s required action: “Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.”[1]

  1. Check whether you use it.Veeam Backup & Replication 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 12 Sep 2023 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, noting that ransomware gangs have used it.[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 81%.[4]

See also

Other Veeam Backup & Replication flaws

Other missing authentication flaws

  • CVE-2026-111357, Ivanti Connect Secure: missing authentication for critical function ·
  • CVE-2026-67277, MikroTik RouterOS: missing authentication for critical function ·
  • CVE-2026-81578, PaperCut NG/MF: missing authentication for critical function ·
  • CVE-2026-72529, TrueConf Server: missing authentication for critical function ·
  • CVE-2026-56164, Microsoft SharePoint Server: missing authentication for critical function ·

Added the same day

Every Veeam flaw on CISA’s list · Everything added in August 2023

References

  1. ^ Cybersecurity and Infrastructure Security Agency. “Veeam Backup & Replication Cloud Connect Missing Authentication for Critical Function Vulnerability”. Known Exploited Vulnerabilities Catalog, added 22 Aug 2023.
  2. ^ National Institute of Standards and Technology. “CVE-2023-27532 Detail”. National Vulnerability Database, published 10 Mar 2023.
  3. ^ Veeam. Advisories and fixes: veeam.com.
  4. ^ FIRST. “Exploit Prediction Scoring System”. EPSS 0.806, percentile 99.6, 31 Oct 2026.
  5. CVE Program. “CVE-2023-27532”. 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.