CVE-2025-59689
CVE-2025-59689 is a security flaw in Libraesva Email Security Gateway. Attackers can run commands on Libraesva Email Security Gateway. The US Cybersecurity and Infrastructure Security Agency (CISA) added it to its catalog of flaws known to be used in attacks on 29 Sep 2025.[1]
Libraesva Email Security Gateway 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. Fixed in version 5.0.31, 5.1.20, 5.2.31 and 5.4.8 and others of Email Security Gateway.
Description
CISA calls it a command injection in Libraesva Email Security Gateway. In its words: “Libraesva Email Security Gateway (ESG) contains a command injection vulnerability which allows command injection via a compressed e-mail attachment.”[1]
The CVE record adds: “Libraesva ESG 4.5 through 5.5.x before 5.5.7 allows command injection via a compressed e-mail attachment. For ESG 5.0 a fix has been released in 5.0.31. For ESG 5.1 a fix has been released in 5.1.20. For ESG 5.2 a fix has been released in 5.2.31. For ESG 5.4 a fix has been released in 5.4.8. For ESG 5.5. a fix has been released in 5.5.7.”[2]
The underlying weakness is command injection (CWE-77), in MITRE’s list of common software weaknesses.
It scores 6.1 out of 10 on the Common Vulnerability Scoring System, which rates it medium, scored by the organisation that published the CVE using CVSS 3.1.[2]
Affected versions
NVD’s record lists these fixed versions: in each line, everything before the version shown is affected.[2]
| Product | Fixed in |
|---|---|
| Email Security Gateway | 5.0.31 |
| Email Security Gateway | 5.1.20 |
| Email Security Gateway | 5.2.31 |
| Email Security Gateway | 5.4.8 |
| Email Security Gateway | 5.5.7 |
Most families won’t have Libraesva Email Security Gateway; it’s for whoever looks after IT at work.
Exploitation
CISA added it to its catalog of known exploited vulnerabilities on 29 Sep 2025, 10 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 20 Oct 2025 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 2%. That’s in the top 20% 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
Libraesva has published a fix or advice.[3] CISA’s required action: “Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.”[1]
- Check whether you use it.Libraesva Email Security Gateway 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.
- Send this page to your IT person.Ask them to confirm it’s fixed (fixed in version 5.0.31, 5.1.20, 5.2.31 and 5.4.8 and others of Email Security Gateway), or not in use. CISA gave US government agencies until 20 Oct 2025 to fix it.
- 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
| Date | Event |
|---|---|
| The flaw is made public in the National Vulnerability Database, with a severity score of 6.1.[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 2%.[4] |
See also
Other command injection flaws
- CVE-2026-105134, AhsayCBS: command injection ·
- CVE-2026-96951, Microsoft Windows: command injection ·
- CVE-2016-3081, Apache Struts: command injection ·
- CVE-2026-8037, Progress LoadMaster: command injection ·
- CVE-2025-29635, D-Link DIR-823X: command injection ·
Added the same day
- CVE-2025-32463, Sudo: inclusion of functionality from untrusted control sphere ·
- CVE-2025-20352, Cisco IOS and IOS XE: software SNMP denial of service and remote code execution ·
- CVE-2025-10035, Fortra GoAnywhere MFT: deserialization of untrusted data ·
- CVE-2021-21311, Adminer: server-side request forgery ·
References
- ^ Cybersecurity and Infrastructure Security Agency. “Libraesva Email Security Gateway Command Injection Vulnerability”. Known Exploited Vulnerabilities Catalog, added 29 Sep 2025.
- ^ National Institute of Standards and Technology. “CVE-2025-59689 Detail”. National Vulnerability Database, published 19 Sep 2025.
- ^ Libraesva. Advisories and fixes: docs.libraesva.com, libraesva.com.
- ^ FIRST. “Exploit Prediction Scoring System”. EPSS 0.020, percentile 80.3, 31 Oct 2026.
- CVE Program. “CVE-2025-59689”. 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.