CVE-2025-49113
CVE-2025-49113 is a security flaw in Roundcube Webmail, webmail software many hosting companies and universities run. Someone who already has a way in can use Roundcube Webmail to run their own code. The US Cybersecurity and Infrastructure Security Agency (CISA) added it to its catalog of flaws known to be used in attacks on 20 Feb 2026.[1]
Roundcube Webmail 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 1.5.10 and 1.6.11 of Webmail.
Description
CISA calls it a deserialization of untrusted data in Roundcube Webmail. In its words: “RoundCube Webmail contains a deserialization of untrusted data vulnerability that allows remote code execution by authenticated users because the _from parameter in a URL is not validated in program/actions/settings/upload.php.”[1]
The underlying weakness is deserialization of untrusted data (CWE-502), in MITRE’s list of common software weaknesses.[2]
It scores 8.8 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 lists these fixed versions: in each line, everything before the version shown is affected.[2]
| Product | Fixed in |
|---|---|
| Webmail | 1.5.10 |
| Webmail | 1.6.11 |
Most families won’t have Roundcube Webmail; it’s for whoever looks after IT at work.
Exploitation
CISA added it to its catalog of known exploited vulnerabilities on 20 Feb 2026, 263 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 13 Mar 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 99%. That’s in the top 1% 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
Roundcube 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.Roundcube Webmail 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 1.5.10 and 1.6.11 of Webmail), or not in use. CISA gave US government agencies until 13 Mar 2026 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 8.8.[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 99%.[4] |
See also
Other Roundcube Webmail flaws
- CVE-2025-68461: cross-site scripting ·
- CVE-2024-42009: cross-site scripting ·
- CVE-2024-37383: cross-site scripting (XSS) ·
- CVE-2020-13965: cross-site scripting (XSS) ·
- CVE-2023-43770: persistent cross-site scripting (XSS) ·
- CVE-2023-5631: persistent cross-site scripting (XSS) ·
Other Roundcube flaws
- CVE-2021-44026, Roundcube Webmail: webmail SQL injection ·
- CVE-2020-35730, Roundcube Webmail: webmail cross-site scripting (XSS) ·
- CVE-2020-12641, Roundcube Webmail: webmail remote code execution ·
- CVE-2017-16651, Roundcube Webmail: webmail file disclosure ·
Other deserialization of untrusted data flaws
- CVE-2021-23758, Ajax.NET Professional: deserialization of untrusted data ·
- CVE-2026-63077, JetBrains TeamCity: deserialization of untrusted data ·
- CVE-2026-50522, Microsoft SharePoint: deserialization of untrusted data ·
- CVE-2026-58644, Microsoft SharePoint: deserialization of untrusted data ·
- CVE-2026-45659, Microsoft SharePoint Server: deserialization of untrusted data ·
Added the same day
- CVE-2025-68461, Roundcube Webmail: cross-site scripting ·
Every Roundcube flaw on CISA’s list · Everything added in February 2026
References
- ^ Cybersecurity and Infrastructure Security Agency. “RoundCube Webmail Deserialization of Untrusted Data Vulnerability”. Known Exploited Vulnerabilities Catalog, added 20 Feb 2026.
- ^ National Institute of Standards and Technology. “CVE-2025-49113 Detail”. National Vulnerability Database, published 2 Jun 2025.
- ^ Roundcube. Advisories and fixes: roundcube.net.
- ^ FIRST. “Exploit Prediction Scoring System”. EPSS 0.995, percentile 99.9, 31 Oct 2026.
- CVE Program. “CVE-2025-49113”. 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.