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CVE-2023-45727

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

CVE-2023-45727 is a security flaw in North Grid Proself. Attackers can read files on North Grid Proself that should be out of reach from anywhere, without logging in. The US Cybersecurity and Infrastructure Security Agency (CISA) added it to its catalog of flaws known to be used in attacks on 3 Dec 2024.[1]

North Grid Proself 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. North Grid has published a fix or advice.

Description

CISA calls it an improper restriction of XML external entity (XXE) reference in North Grid Proself. In its words: “North Grid Proself Enterprise/Standard, Gateway, and Mail Sanitize contain an improper restriction of XML External Entity (XXE) reference vulnerability, which could allow a remote, unauthenticated attacker to conduct an XXE attack.”[1]

The CVE record adds: “Proself Enterprise/Standard Edition Ver5.62 and earlier, Proself Gateway Edition Ver1.65 and earlier, and Proself Mail Sanitize Edition Ver1.08 and earlier allow a remote unauthenticated attacker to conduct XML External Entity (XXE) attacks. By processing a specially crafted request containing malformed XML data, arbitrary files on the server containing account information may be read by the attacker.”[2]

The underlying weakness is XML external entity (CWE-611), 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 NVD using CVSS 3.1.[2]

Affected versions

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

Most families won’t have North Grid Proself; it’s for whoever looks after IT at work.

Exploitation

CISA added it to its catalog of known exploited vulnerabilities on 3 Dec 2024, 412 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 24 Dec 2024 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 5%. That’s in the top 9% 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

North Grid 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.North Grid Proself 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 24 Dec 2024 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 5%.[4]

See also

Other XML external entity flaws

  • CVE-2025-58360, OSGeo GeoServer: improper restriction of XML external entity reference ·
  • CVE-2025-2776, SysAid On-Prem: on-prem improper restriction of XML external entity reference ·
  • CVE-2025-2775, SysAid On-Prem: on-prem improper restriction of XML external entity reference ·
  • CVE-2024-34102, Adobe Commerce and Magento Open Source: improper restriction of XML external entity reference (XXE) ·
  • CVE-2019-9670, Synacor Zimbra Collaboration Suite (ZCS): improper restriction of XML external entity reference ·

Added the same day

References

  1. ^ Cybersecurity and Infrastructure Security Agency. “North Grid Proself Improper Restriction of XML External Entity (XXE) Reference Vulnerability”. Known Exploited Vulnerabilities Catalog, added 3 Dec 2024.
  2. ^ National Institute of Standards and Technology. “CVE-2023-45727 Detail”. National Vulnerability Database, published 18 Oct 2023.
  3. ^ North Grid. Advisories and fixes: proself.jp.
  4. ^ FIRST. “Exploit Prediction Scoring System”. EPSS 0.048, percentile 92.0, 31 Oct 2026.
  5. CVE Program. “CVE-2023-45727”. 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.