CVE-2026-103321
MISP Stored Cross-Site Scripting (XSS) via Unvalidated Event Graph Preview Image
MISP contains a stored cross-site script (XSS) vulnerability in the event graph preview feature.
The event graph preview image field was accepted and stored without server-side validation. On the client side, the stored value was rendered into an HTML img element's src attribute via string concatenation, allowing a crafted value to break out of the attribute context and inject arbitrary script.
Preconditions:
-
An authenticated MISP user with the ability to create or modify an event graph entry.
-
A second user (the victim) who views the event graph and triggers the preview popover.
Impact:
-
Execution of arbitrary JavaScript in the victim's browser within the MISP application context.
-
Potential theft of session tokens, cookies, or sensitive data accessible to the victim's browser.
-
Potential for performing actions on behalf of the victim within the MISP application.
Affected: MISP versions prior to the fix (commit applied after v2.5.48).
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- Passive
What an attacker can affect
- Confidentiality
- None
- Integrity
- High
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
MISP Stored Cross-Site Scripting (XSS) via Unvalidated Event Graph Preview Image
MISP contains a stored cross-site script (XSS) vulnerability in the event graph preview feature.
The event graph preview image field was accepted and stored without server-side validation. On the client side, the stored value was rendered into an HTML img element's src attribute via string concatenation, allowing a crafted value to break out of the attribute context and inject arbitrary script.
Preconditions:
-
An authenticated MISP user with the ability to create or modify an event graph entry.
-
A second user (the victim) who views the event graph and triggers the preview popover.
Impact:
-
Execution of arbitrary JavaScript in the victim's browser within the MISP application context.
-
Potential theft of session tokens, cookies, or sensitive data accessible to the victim's browser.
-
Potential for performing actions on behalf of the victim within the MISP application.
Affected: MISP versions prior to the fix (commit applied after v2.5.48).
- Record
CVE-2026-103321- CVSS 4.0
- 8.3 High
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:H/VA:N/SC:H/SI:H/SA:N - Weakness
- CWE-79, CWE-20
- Updated
- 2026-11-02
EUVDEUVD-2026-89800
MISP contains a stored cross-site script (XSS) vulnerability in the event graph preview feature.
The event graph preview image field was accepted and stored without server-side validation. On the client side, the stored value was rendered into an HTML img element's src attribute via string concatenation, allowing a crafted value to break out of the attribute context and inject arbitrary script.
Preconditions:
-
An authenticated MISP user with the ability to create or modify an event graph entry.
-
A second user (the victim) who views the event graph and triggers the preview popover.
Impact:
-
Execution of arbitrary JavaScript in the victim's browser within the MISP application context.
-
Potential theft of session tokens, cookies, or sensitive data accessible to the victim's browser.
-
Potential for performing actions on behalf of the victim within the MISP application.
Affected: MISP versions prior to the fix (commit applied after v2.5.48).
- Record
EUVD-2026-89800- CVSS 4.0
- 8.3 High
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:H/VA:N/SC:H/SI:H/SA:N - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-w4mv-4x7w-vpvv
MISP contains a stored cross-site script (XSS) vulnerability in the event graph preview feature. ...
MISP contains a stored cross-site script (XSS) vulnerability in the event graph preview feature.
The event graph preview image field was accepted and stored without server-side validation. On the client side, the stored value was rendered into an HTML img element's src attribute via string concatenation, allowing a crafted value to break out of the attribute context and inject arbitrary script.
Preconditions:
-
An authenticated MISP user with the ability to create or modify an event graph entry.
-
A second user (the victim) who views the event graph and triggers the preview popover.
Impact:
-
Execution of arbitrary JavaScript in the victim's browser within the MISP application context.
-
Potential theft of session tokens, cookies, or sensitive data accessible to the victim's browser.
-
Potential for performing actions on behalf of the victim within the MISP application.
Affected: MISP versions prior to the fix (commit applied after v2.5.48).
- Record
GHSA-w4mv-4x7w-vpvv- CVSS 4.0
- 8.3 High
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:H/VA:N/SC:H/SI:H/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 - Weakness
- CWE-20
- Updated
- 2026-11-02
NVD
MISP contains a stored cross-site script (XSS) vulnerability in the event graph preview feature.
The event graph preview image field was accepted and stored without server-side validation. On the client side, the stored value was rendered into an HTML img element's src attribute via string concatenation, allowing a crafted value to break out of the attribute context and inject arbitrary script.
Preconditions:
-
An authenticated MISP user with the ability to create or modify an event graph entry.
-
A second user (the victim) who views the event graph and triggers the preview popover.
Impact:
-
Execution of arbitrary JavaScript in the victim's browser within the MISP application context.
-
Potential theft of session tokens, cookies, or sensitive data accessible to the victim's browser.
-
Potential for performing actions on behalf of the victim within the MISP application.
Affected: MISP versions prior to the fix (commit applied after v2.5.48).
- Record
CVE-2026-103321- CVSS 4.0
- 8.3 High
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:H/VA:N/SC:H/SI:H/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 - Weakness
- CWE-20, CWE-79
- Updated
- 2026-11-02
OSV
MISP Stored Cross-Site Scripting (XSS) via Unvalidated Event Graph Preview Image
MISP contains a stored cross-site script (XSS) vulnerability in the event graph preview feature.
The event graph preview image field was accepted and stored without server-side validation. On the client side, the stored value was rendered into an HTML img element's src attribute via string concatenation, allowing a crafted value to break out of the attribute context and inject arbitrary script.
Preconditions:
-
An authenticated MISP user with the ability to create or modify an event graph entry.
-
A second user (the victim) who views the event graph and triggers the preview popover.
Impact:
-
Execution of arbitrary JavaScript in the victim's browser within the MISP application context.
-
Potential theft of session tokens, cookies, or sensitive data accessible to the victim's browser.
-
Potential for performing actions on behalf of the victim within the MISP application.
Affected: MISP versions prior to the fix (commit applied after v2.5.48).
- Record
CVE-2026-103321- CVSS 4.0
- 8.3 High
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:H/VA:N/SC:H/SI:H/SA:N - Weakness
- CWE-20, 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-2026-103321 is a high vulnerability (CVSS 8.3) in Misp, published September 30, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.36%, the 29th percentile. No source names a fixed version.