CVE-2026-74998: Roundcube Webmail · XSS or 'Cross-site Scripting'
Affects Roundcube WebmailSource CVE Database V5
Not known to be exploited · CVSS 7.2 High : upgrade to 1.7.3 or 1.6.18 soon.
Data as of 14 Nov 2026, 20:44 UTC
- EPSS
- 0.3% chance of exploitation in 30 days – higher than 25% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 1.7.3, 1.6.18
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:NExploitation evidence
Disclosed: evidence found.
CVE published 17 Aug 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: 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 14 Nov 2026.
What to do
Upgrade Roundcube Webmail to 1.7.3 or 1.6.18.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| RoundcubeWebmail | Affected
| Fixed in
|
| RoundcubeWebmail | Affected
| Fixed in
|
GitHubroundcube/roundcubemailpkg:github/roundcube/roundcubemailOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
Until then, consider applying any recommended temporary mitigations from the vendor if provided.
Description
CVE-2026-74998 is a high-severity cross-site scripting (XSS) vulnerability in Roundcube Webmail. It affects versions before 1.6.18 and 1.7.x before 1.7.3. The issue arises because responses from the CSS proxy were not properly validated, potentially allowing information disclosure or XSS attacks via MIME sniffing.
References
- roundcube.net/news/2026/08/09/security-updates-1.6.18-and-1.7.3 (opens in a new tab)
- github.com/roundcube/roundcubemail/releases/tag/1.6.18 (opens in a new tab)
- github.com/roundcube/roundcubemail/commit/62d33c8a0dc3fd0dd03984220dc9709e8e0de43b (opens in a new tab)
- github.com/roundcube/roundcubemail/releases/tag/1.7.3 (opens in a new tab)
- github.com/roundcube/roundcubemail/commit/a2334990c02f7cb77b1a8d6fa97fcd9e1b5cd1fb (opens in a new tab)