RoundCube Webmail Deserialization of Untrusted Data
CVE-2025-49113 is a high-severity deserialization of untrusted data vulnerability in Webmail from Roundcube, with a CVSS 3.1 base score of 8.8 out of 10. It can be exploited remotely over the network by an attacker with a low-privileged account, without any action from a user. The record lists versions 1.5.10, 1.6.11 as the first without the flaw, so updating Webmail to one of those releases or later removes the exposure. CISA added it to the Known Exploited Vulnerabilities catalogue on February 20, 2026, which means attacks have been observed in the wild.
Attackers are already exploiting this vulnerability, according to CISA.
What to do
- Update Webmail to 1.5.10 or 1.6.11, whichever matches your release line, or a later version.
- 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.
- Read the advisory on roundcube.net for workarounds and exact fixed builds.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Roundcube | Webmail | before 1.5.10; 1.6.0 up to, but not including, 1.6.11 | 1.5.10, 1.6.11 |
| Debian | Debian Linux | 11.0 | Not stated |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 9.9 | Critical | CNA (mitre.org) |
| CVSS 3.1 | 8.8 | High | NVD |
Official description
Roundcube Webmail before 1.5.10 and 1.6.x before 1.6.11 allows remote code execution by authenticated users because the _from parameter in a URL is not validated in program/actions/settings/upload.php, leading to PHP Object Deserialization.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Deserialization of Untrusted Data
The product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid.
How developers prevent this class of flaw
- If available, use the signing/sealing features of the programming language to assure that deserialized data has not been tainted. For example, a hash-based message authentication code (HMAC) could be used to ensure that data has not been modified.
- When deserializing data, populate a new object rather than just deserializing. The result is that the data flows through safe input validation and that the functions are safe.
- Explicitly define a final object() to prevent deserialization.
More Deserialization of Untrusted Data vulnerabilities (CWE-502)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: active, automatable: no, technical impact: total).
- Added to CISA's Known Exploited Vulnerabilities catalogue.
- Deadline for US federal agencies to remediate, set by CISA.
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- github.com/roundcube/roundcubemail/commit/0376f69e958a8fef7f6f09e352c541b4e7729c4d
- github.com/roundcube/roundcubemail/commit/7408f31379666124a39f9cb1018f62bc5e2dc695
- github.com/roundcube/roundcubemail/commit/c50a07d88ca38f018a0f4a0b008e9a1deb32637e
- github.com/roundcube/roundcubemail/pull/9865Issue Tracking
- github.com/roundcube/roundcubemail/releases/tag/1.5.10Release Notes
- github.com/roundcube/roundcubemail/releases/tag/1.6.11Release Notes
- vicarius.io/vsociety/posts/cve-2025-49113-roundcube-mitigation-scriptExploit, Mitigation, Third Party Advisory
- vicarius.io/vsociety/posts/cve-2025-49113-roundcube-vulnerability-detectionExploit, Mitigation, Third Party Advisory
Third-party and government advisories
- fearsoff.org/research/roundcubeThird Party Advisory
- openwall.com/lists/oss-security/2025/06/02/3Mailing List, Third Party Advisory
- lists.debian.org/debian-lts-announce/2025/06/msg00008.htmlMailing List, Third Party Advisory
- cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-49113US Government Resource
Other vulnerabilities in Webmail
- 8.1 High severity
- 7.2 High severity
- 8.3 High severity
- 8.1 High severity
- 7.1 High severity
- 8.5 High severity
Recent Deserialization of Untrusted Data vulnerabilities
- 9.0 Critical severity
- 8.8 High severity
- 9.8 Critical severity
- 7.2 High severity
- 9.1 Critical severity
- 7.8 High severity
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