CVE-2026-113583
Cypht 2.0.0 through 2.12.2 Stored DOM XSS via externalResources.js
Cypht webmail 2.0.0 through 2.12.2 contains a DOM-based cross-site scripting vulnerability that allows remote attackers to execute arbitrary JavaScript by crafting malicious alt text or URL values in an HTML email's external image tag when ALLOW_EXTERNAL_IMAGE_SOURCES is enabled. Attackers can send a specially crafted email so that when the victim opens it, the externalResources.js code builds the blocked-image notice using innerHTML with decoded email-derived values, triggering script execution in the victim's authenticated session to read mailboxes, send email, or change settings.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- Passive
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
Cypht 2.0.0 through 2.12.2 Stored DOM XSS via externalResources.js
Cypht webmail 2.0.0 through 2.12.2 contains a DOM-based cross-site scripting vulnerability that allows remote attackers to execute arbitrary JavaScript by crafting malicious alt text or URL values in an HTML email's external image tag when ALLOW_EXTERNAL_IMAGE_SOURCES is enabled. Attackers can send a specially crafted email so that when the victim opens it, the externalResources.js code builds the blocked-image notice using innerHTML with decoded email-derived values, triggering script execution in the victim's authenticated session to read mailboxes, send email, or change settings.
- Record
CVE-2026-113583- CVSS 4.0
- 5.3 Medium
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N - CVSS 3.1
- 6.1 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N - Weakness
- CWE-79
- Updated
- 2026-11-02
EUVDEUVD-2026-104966
Cypht webmail 2.0.0 through 2.12.2 contains a DOM-based cross-site scripting vulnerability that allows remote attackers to execute arbitrary JavaScript by crafting malicious alt text or URL values in an HTML email's external image tag when ALLOW_EXTERNAL_IMAGE_SOURCES is enabled. Attackers can send a specially crafted email so that when the victim opens it, the externalResources.js code builds the blocked-image notice using innerHTML with decoded email-derived values, triggering script execution in the victim's authenticated session to read mailboxes, send email, or change settings.
- Record
EUVD-2026-104966- CVSS 4.0
- 5.3 Medium
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-w69r-hqpc-72f2
Cypht webmail 2.0.0 through 2.12.2 contains a DOM-based cross-site scripting vulnerability that...
Cypht webmail 2.0.0 through 2.12.2 contains a DOM-based cross-site scripting vulnerability that allows remote attackers to execute arbitrary JavaScript by crafting malicious alt text or URL values in an HTML email's external image tag when ALLOW_EXTERNAL_IMAGE_SOURCES is enabled. Attackers can send a specially crafted email so that when the victim opens it, the externalResources.js code builds the blocked-image notice using innerHTML with decoded email-derived values, triggering script execution in the victim's authenticated session to read mailboxes, send email, or change settings.
- Record
GHSA-w69r-hqpc-72f2- CVSS 4.0
- 5.3 Medium
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - CVSS 3.1
- 6.1 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N - Weakness
- CWE-79
- Updated
- 2026-11-02
NVD
Cypht webmail 2.0.0 through 2.12.2 contains a DOM-based cross-site scripting vulnerability that allows remote attackers to execute arbitrary JavaScript by crafting malicious alt text or URL values in an HTML email's external image tag when ALLOW_EXTERNAL_IMAGE_SOURCES is enabled. Attackers can send a specially crafted email so that when the victim opens it, the externalResources.js code builds the blocked-image notice using innerHTML with decoded email-derived values, triggering script execution in the victim's authenticated session to read mailboxes, send email, or change settings.
- Record
CVE-2026-113583- CVSS 4.0
- 5.3 Medium
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - CVSS 3.1
- 6.1 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N - Weakness
- CWE-79
- Updated
- 2026-11-02
OSV
Cypht 2.0.0 through 2.12.2 Stored DOM XSS via externalResources.js
Cypht webmail 2.0.0 through 2.12.2 contains a DOM-based cross-site scripting vulnerability that allows remote attackers to execute arbitrary JavaScript by crafting malicious alt text or URL values in an HTML email's external image tag when ALLOW_EXTERNAL_IMAGE_SOURCES is enabled. Attackers can send a specially crafted email so that when the victim opens it, the externalResources.js code builds the blocked-image notice using innerHTML with decoded email-derived values, triggering script execution in the victim's authenticated session to read mailboxes, send email, or change settings.
- Record
CVE-2026-113583- CVSS 4.0
- 5.3 Medium
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N - Weakness
- CWE-79
- Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-113583 is a medium vulnerability (CVSS 5.3) in Cypht-org Cypht, published October 20, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.39%, the 33rd percentile. No source names a fixed version.
References
github.com/cypht-org/cypht/pull/2118/changes/75d2fb83d228be2aaa37036a11eea68d82122d85
vulncheck.com/advisories/cypht-through-stored-dom-xss-via-externalresources-js
nvd.nist.gov/vuln/detail/CVE-2026-113583