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CVE Record

CVE-2025-48700: An issue was discovered in Zimbra Collaboration (ZCS) 8.8.15 and 9.0 and 10.0 and 10.1.

An issue was discovered in Zimbra Collaboration (ZCS) 8.8.15 and 9.0 and 10.0 and 10.1. A Cross-Site Scripting (XSS) vulnerability in the Zimbra Classic UI allows attackers to execute arbitrary JavaScript within the user's session, potentially leading to unauthorized access to sensitive information. This issue arises from insufficient sanitization of HTML content, specifically involving crafted tag structures and attribute values that include an @import directive and other script injection vectors. The vulnerability is triggered when a user views a crafted e-mail message in the Classic UI, requiring no additional user interaction.

MediumCVSS 6.1Known exploitedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

CVE-2025-48700 is a Zimbra Classic UI email-viewing XSS issue. A crafted email can run JavaScript in a user’s webmail session when opened, without further clicks. That can expose sensitive mailbox data or enable session misuse. CISA KEV listing means exploitation has been observed or is officially treated as known exploited.

Executive priority

Treat this as urgent for Zimbra environments because it is KEV-listed and can be triggered by viewing email. Prioritize remediation for internet-facing webmail and sensitive users, while relying on Zimbra’s advisory for exact fixes.

Technical view

The flaw is CWE-79 in Zimbra Collaboration Classic UI for ZCS 8.8.15, 9.0, 10.0, and 10.1. Insufficient HTML sanitization of crafted tag structures and attribute values, including @import-related vectors, allows arbitrary JavaScript execution in the viewing user’s session. CVSS is 6.1, with user interaction required through viewing email.

Likely exposure

Organizations running Zimbra Collaboration with Classic UI exposed to users are the main concern, especially externally reachable webmail portals and privileged mailbox users. Evidence does not identify other products or specific patch levels beyond the listed ZCS branches.

Exploitation context

The source bundle marks this CVE as in CISA KEV, so active exploitation is supported. Public details here describe the trigger as viewing a crafted email in Classic UI, but do not provide campaign details, exploit tooling, or indicators.

Researcher notes

Evidence is strong for vulnerability class, affected ZCS branches, Classic UI trigger, and KEV status. The bundle does not include a named fixed version, workaround, indicators, or exploit timeline, so remediation details should be taken directly from Zimbra guidance.

Mitigation direction

  • Check Zimbra Security Advisories for fixed releases or workarounds for each deployed branch.
  • Apply vendor-provided updates or mitigations for affected ZCS versions.
  • Prioritize Classic UI deployments and high-value mail users first.
  • If vendor guidance supports it, reduce Classic UI use until remediated.
  • Monitor mailbox and webmail session activity for suspicious access.

Validation and detection

  • Inventory ZCS versions and confirm whether Classic UI is enabled or used.
  • Compare installed builds against Zimbra Security Advisories and Security Center guidance.
  • Review webmail logs for suspicious sessions involving unexpected mailbox access.
  • Confirm remediation through vendor-documented version checks or supported validation steps.
  • Assess whether exposed webmail users include administrators or sensitive mailboxes.
Prepared
Confidence
high
Sources
6

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cwe · medium confidence lookup

CWE-79: User-session and phishing behavior lookup

Client-side and session-facing weaknesses should be reviewed alongside initial-access and user-execution behaviors. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

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cve · low confidence lookup

CVE-2025-48700 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

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Vulnerability profileCVE Program record
Severity
Medium
CVSS
6.1 (3.1)
Known Exploited
Yes
Published

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

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

1CVSS vectors
0Timeline events
0ADP providers
5Source links

CISA KEV status

Status
Known exploited
Source
CISA / ADP
Date added
Not provided

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
6.1CVSS 3.1MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N2.82.7Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

6.1Medium
CVSS 3.1 vector shape for CVE-2025-48700Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

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

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
n/an/an/aListed
Weakness

CWE details

CWE-79

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.