LiveActive security incident?Get immediate response
CVE Record

CVE-2009-4629: Mozilla Necko, as used in Thunderbird 3.0.1, SeaMonkey, and other applications, performs DNS prefetching ev...

Mozilla Necko, as used in Thunderbird 3.0.1, SeaMonkey, and other applications, performs DNS prefetching even when the app type is APP_TYPE_MAIL or APP_TYPE_EDITOR, which makes it easier for remote attackers to determine the network location of the application's user by logging DNS requests, as demonstrated by DNS requests triggered by reading text/plain e-mail messages in Thunderbird.

UnknownCVSS not scoredNot KEV-listedUpdated
Discuss exposureBack to CVEs
Glexia's TakeAutomated analysislow

Security readout for executives and security teams

Plain-English summary

This issue could let an external sender learn information about where a user is on the network when a vulnerable Mozilla-based mail or editor application processes content. It is primarily a privacy and exposure concern, not evidence of code execution or system takeover in the supplied sources.

Executive priority

Handle as a low-urgency legacy privacy issue unless sensitive users still operate affected Mozilla-based clients. Prioritize inventory and retirement of unsupported software over emergency response.

Technical view

Mozilla Necko performed DNS prefetching even for mail or editor application types. The CVE describes DNS lookups being triggered by reading plain-text email in Thunderbird 3.0.1, allowing an attacker who controls DNS logging to infer user network location.

Likely exposure

Likely exposure is limited to legacy Thunderbird 3.0.1, SeaMonkey, or other applications using affected Mozilla Necko behavior. Current exposure cannot be confirmed from the supplied bundle.

Exploitation context

The source bundle describes a remote attacker logging DNS requests to infer a user's network location. It does not cite active exploitation, public weaponization, KEV listing, or impact beyond DNS-based privacy leakage.

Researcher notes

Evidence is narrow: the CVE description names Thunderbird 3.0.1, SeaMonkey, and other Necko users, with a demonstrated plain-text email trigger. No CVSS, CWE, patch detail, or exploitation confirmation is included in the bundle.

Mitigation direction

  • Identify legacy Thunderbird, SeaMonkey, and Mozilla Necko-based mail or editor applications.
  • Check Mozilla Bugzilla and vendor guidance for the corrected behavior or supported configuration.
  • Retire or upgrade unsupported legacy clients according to vendor guidance.
  • Consider DNS egress monitoring for unexpected lookups from mail clients.

Validation and detection

  • Inventory mail and editor applications using Mozilla Necko components.
  • Review affected client versions against the CVE and Mozilla bug reference.
  • Check DNS logs for unexpected lookups originating from mail-client activity.
  • Confirm vendor guidance before treating any configuration change as a fix.
Prepared
Confidence
medium
Sources
4

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.

cve · low confidence lookup

CVE-2009-4629 mapping review

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

Open ATT&CK lookup
Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
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.

0CVSS vectors
0Timeline events
0ADP providers
3Source links

CVSS and timeline data

No CVSS vectors or timeline events were available in the normalized CVE source material.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
n/an/an/aListed
Weakness

CWE details

No CWE listed

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