VulnerabilityPublished 17 Aug 2026

CVE-2026-75006: Roundcube Webmail · Server-Side Request Forgery (SSRF)

Affects Roundcube WebmailSource CVE Database V5

Mentioned vulnerabilities

Not known to be exploited · CVSS 5.8 Medium : upgrade to 1.7.3 or 1.6.18 when convenient.

Data as of 26 Oct 2026, 10:12 UTC

CVSS 3.1 base score

5.8Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS

0.4% chance of exploitation in 30 days – higher than 35% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

Exploitation: No evidence of active exploitation and no public proof of concept
Automatable: Attackers can reliably automate steps 1–4 of the kill chain
Technical impact: Limited control over the software or limited information exposure

CISA SSVC assessment, 2026-08-17.

Patch

Available – fixed in 1.7.3, 1.6.18

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Changed
Confidentiality: None
Integrity: Low
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Changed: An exploited vulnerability can affect resources beyond the security scope managed by the security authority of the vulnerable component. In this case, the vulnerable component and the impacted component are different and managed by different security authorities.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact on the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 17 Aug 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade Roundcube Webmail to 1.7.3 or 1.6.18.

Affected software

Product	Affected	Fixed in
RoundcubeWebmail	Affected >=1.7.0 <1.7.3	Fixed in 1.7.3
RoundcubeWebmail	Affected >=1.6.0 <1.6.18	Fixed in 1.6.18

AI-suggested

Upgrade Roundcube Webmail to version 1.6.18 or later, or 1.7.3 or later, where this vulnerability is fixed. No other mitigation is indicated by the vendor advisory. Since this is not a cloud service, patching the affected software versions is required to remediate the issue.

Description

CVE-2026-75006 is a Server-Side Request Forgery (SSRF) vulnerability in Roundcube Webmail versions before 1.6.18 and 1.7.3. It arises from insufficient sanitization of CSS in HTML email messages, allowing malicious stylesheet links to potentially access local network hosts. This vulnerability is due to incomplete fixes of previous related CVEs. The issue has a medium severity rating with a CVSS score of 5.8.

Impact

An attacker can craft HTML emails with malicious CSS that causes the Roundcube Webmail server to make unauthorized requests to internal network hosts, potentially leading to information disclosure. The vulnerability does not impact confidentiality directly but can lead to limited information leakage. There is no indication of availability or integrity impact. No known exploits are reported in the wild.

Summary

Roundcube Webmail versions >=1.6.0 <1.6.18 and >=1.7.0 <1.7.3 contain a SSRF vulnerability (CWE-918) caused by insufficient sanitization of Cascading Style Sheets (CSS) in HTML email messages. Malicious emails with stylesheet links can trigger SSRF or information disclosure by accessing internal network resources. This vulnerability is a regression or incomplete fix of earlier vulnerabilities CVE-2026-35540, CVE-2026-48843, and CVE-2026-62643. The issue is fixed in versions 1.6.18 and 1.7.3.

CWE-918Server-Side Request Forgery (SSRF) (opens in a new tab)
Base weaknessCWE Top 25 (2025): #22OWASP Top 10 A01:2025: Broken Access Control (opens in a new tab)
The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination.
OWASP Cheat Sheets
Server Side Request Forgery Prevention (opens in a new tab)
Unvalidated Redirects and Forwards (opens in a new tab)
Cross Site Scripting Prevention (opens in a new tab)
DOM based XSS Prevention (opens in a new tab)
Authorization (opens in a new tab)
OWASP ASVS 4.0.3
V12.6.1 (opens in a new tab)
V5.2.6 (opens in a new tab)
Attack patterns
Server Side Request Forgery (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

Community reviews

Loading reviews…

Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 26 Oct 2026, 09:26 UTC

WeaknessesCWE-918

Technical details

References

Community reviews

Related threats