01 Record

CVE-2026-88921

MISP: Unescaped HTML Injection in PDF Report Element Rendering

MediumPUBLISHEDCNA: CIRCL

CNA base score5.1 CVSS v4.0CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N

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02 Description

MISP: Unescaped HTML Injection in PDF Report Element Rendering

03 Exploitation and scoring

Exploitation

Assessed, none found. CISA's assessment recorded neither public exploit code nor evidence of exploitation when it was made.

SSVC decision

ExploitationnoneCISA recorded no public exploit code and no evidence of exploitation.
AutomatablenoAt least one step from reconnaissance to exploitation cannot be reliably automated.
Technical ImpactpartialSuccessful exploitation gives limited control of the vulnerable component.

CISA publishes the decision points, not a final SSVC decision. The decision also depends on mission and well-being impact, which is a property of your deployment rather than of the vulnerability.

EPSS probability

0.49% probability of exploitation activity in the next 30 days.

EPSS percentile

Equal to or higher than the score of 41.9% of scored records. A rank, not a probability.

NVD base score

5.1 (CVSS v4.0), scored by the NVD independently of the CNA.

NVD CVSS vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/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

NVD analysis status

Deferred. NVD last modified this record on 2026-09-10.

Red Hat severity

No Red Hat rating. Red Hat rates the CVEs that affect its products.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

04 Metadata

Published

2026-09-10 13:41Z1 MO AGO

Last updated

2026-09-10 17:02Z1 MO AGO

Reserved

2026-09-10

Assigning CNA

CIRCL

Record state

PUBLISHED

Severity

Medium (CVSS 5.1)

CNA CVSS vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N

Weaknesses

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')Base
CWE-116Improper Encoding or Escaping of OutputClass

Data version

5.2

Document digest

d14f249ef08120e3fdbb50860f33963497a5f4f4829d8e662c2ee699f0f077f2

05 Affected products

VendorProductVersionsPlatforms

MISPMISP< 2.5.46—

06 References

github.comSecurity patchhttps://github.com/MISP/MISP/commit/949744a4bpatch

07 Remediation

The fix applies HTML entity encoding (via the h() helper, which wraps htmlspecialchars with ENT_QUOTES and UTF-8) to every user-controlled value interpolated into the HTML templates in the MISPElementHTMLFormatterTool. This ensures that attribute types, values, object names, relations, tag names, and colour values are treated as inert data and cannot inject markup or break out of the surrounding span/style context. The hardcoded sample values in the attribute() template are replaced with proper %s format placeholders so that the actual element data is rendered. Comprehensive unit tests are added to verify both correct rendering and escaping of hostile inputs across all four formatter methods.