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CVE-2023-7101

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

CVE-2023-7101 is a security flaw in Spreadsheet::ParseExcel. Attackers can run their own code on Spreadsheet::ParseExcel. The US Cybersecurity and Infrastructure Security Agency (CISA) added it to its catalog of flaws known to be used in attacks on 2 Jan 2024.[1]

Spreadsheet::ParseExcel 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. Spreadsheet::ParseExcel has published a fix or advice.

Description

CISA calls it a remote code execution in Spreadsheet::ParseExcel Spreadsheet::ParseExcel. In its words: “Spreadsheet::ParseExcel contains a remote code execution vulnerability due to passing unvalidated input from a file into a string-type “eval”. Specifically, the issue stems from the evaluation of Number format strings within the Excel parsing logic.”[1]

The CVE record adds: “Spreadsheet::ParseExcel version 0.65 is a Perl module used for parsing Excel files. Spreadsheet::ParseExcel is vulnerable to an arbitrary code execution (ACE) vulnerability due to passing unvalidated input from a file into a string-type “eval”. Specifically, the issue stems from the evaluation of Number format strings (not to be confused with printf-style format strings) within the Excel parsing logic.”[2]

The underlying weakness is CWE-95, in MITRE’s list of common software weaknesses.

It scores 7.8 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; Spreadsheet::ParseExcel’s advisory has them[3]. CISA names the product as Spreadsheet::ParseExcel Spreadsheet::ParseExcel.

Most families won’t have Spreadsheet::ParseExcel; it’s for whoever looks after IT at work.

Exploitation

CISA added it to its catalog of known exploited vulnerabilities on 2 Jan 2024, 9 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 23 Jan 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 19%. That’s in the top 3% of the flaws it scores.[4]

CISA assesses it as not automatable: each attack takes some work.

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

Fix

Spreadsheet::ParseExcel 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.Spreadsheet::ParseExcel 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 23 Jan 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 7.8.[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 19%.[4]

See also

Similar flaws

Added the same day

  • CVE-2023-7024, Chrome and other Chromium browsers: heap buffer overflow ·

References

  1. ^ Cybersecurity and Infrastructure Security Agency. “Spreadsheet::ParseExcel Remote Code Execution Vulnerability”. Known Exploited Vulnerabilities Catalog, added 2 Jan 2024.
  2. ^ National Institute of Standards and Technology. “CVE-2023-7101 Detail”. National Vulnerability Database, published 24 Dec 2023.
  3. ^ Spreadsheet::ParseExcel. Advisories and fixes: metacpan.org, barracuda.com.
  4. ^ FIRST. “Exploit Prediction Scoring System”. EPSS 0.190, percentile 97.3, 31 Oct 2026.
  5. CVE Program. “CVE-2023-7101”. 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.