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Vulnerability details: VCID-6kgm-9pss-vkfv
Vulnerability ID VCID-6kgm-9pss-vkfv
Aliases CVE-2025-3877
Summary A crafted HTML email using mailbox:/// links can trigger automatic, unsolicited downloads of .pdf files to the user's desktop or home directory without prompting, even if auto-saving is disabled. This behavior can be abused to fill the disk with garbage data (e.g. using /dev/urandom on Linux) or to leak Windows credentials via SMB links when the email is viewed in HTML mode. While user interaction is required to download the .pdf file, visual obfuscation can conceal the download trigger. Viewing the email in HTML mode is enough to load external content.
Status Published
Exploitability 0.5
Weighted Severity 8.0
Risk 4.0
Affected and Fixed Packages Package Details
Weaknesses (1)
CWE-200 Exposure of Sensitive Information to an Unauthorized Actor
System Score Found at
cvssv3 5.4 https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2025-3877.json
epss 0.00017 https://api.first.org/data/v1/epss?cve=CVE-2025-3877
epss 0.00031 https://api.first.org/data/v1/epss?cve=CVE-2025-3877
epss 0.00031 https://api.first.org/data/v1/epss?cve=CVE-2025-3877
epss 0.00031 https://api.first.org/data/v1/epss?cve=CVE-2025-3877
epss 0.00034 https://api.first.org/data/v1/epss?cve=CVE-2025-3877
epss 0.00034 https://api.first.org/data/v1/epss?cve=CVE-2025-3877
epss 0.00034 https://api.first.org/data/v1/epss?cve=CVE-2025-3877
epss 0.00034 https://api.first.org/data/v1/epss?cve=CVE-2025-3877
epss 0.00034 https://api.first.org/data/v1/epss?cve=CVE-2025-3877
epss 0.00034 https://api.first.org/data/v1/epss?cve=CVE-2025-3877
epss 0.00034 https://api.first.org/data/v1/epss?cve=CVE-2025-3877
epss 0.00034 https://api.first.org/data/v1/epss?cve=CVE-2025-3877
epss 0.00034 https://api.first.org/data/v1/epss?cve=CVE-2025-3877
epss 0.00034 https://api.first.org/data/v1/epss?cve=CVE-2025-3877
epss 0.00034 https://api.first.org/data/v1/epss?cve=CVE-2025-3877
epss 0.00034 https://api.first.org/data/v1/epss?cve=CVE-2025-3877
epss 0.00034 https://api.first.org/data/v1/epss?cve=CVE-2025-3877
epss 0.00034 https://api.first.org/data/v1/epss?cve=CVE-2025-3877
epss 0.00034 https://api.first.org/data/v1/epss?cve=CVE-2025-3877
epss 0.00034 https://api.first.org/data/v1/epss?cve=CVE-2025-3877
epss 0.00036 https://api.first.org/data/v1/epss?cve=CVE-2025-3877
epss 0.00036 https://api.first.org/data/v1/epss?cve=CVE-2025-3877
epss 0.00036 https://api.first.org/data/v1/epss?cve=CVE-2025-3877
epss 0.00036 https://api.first.org/data/v1/epss?cve=CVE-2025-3877
epss 0.00036 https://api.first.org/data/v1/epss?cve=CVE-2025-3877
epss 0.00036 https://api.first.org/data/v1/epss?cve=CVE-2025-3877
cvssv3.1 5.4 https://bugzilla.mozilla.org/show_bug.cgi?id=1958580
ssvc Track https://bugzilla.mozilla.org/show_bug.cgi?id=1958580
generic_textual high https://www.mozilla.org/en-US/security/advisories/mfsa2025-34
generic_textual high https://www.mozilla.org/en-US/security/advisories/mfsa2025-35
cvssv3.1 5.4 https://www.mozilla.org/security/advisories/mfsa2025-34/
ssvc Track https://www.mozilla.org/security/advisories/mfsa2025-34/
cvssv3.1 5.4 https://www.mozilla.org/security/advisories/mfsa2025-35/
ssvc Track https://www.mozilla.org/security/advisories/mfsa2025-35/
Reference id Reference type URL
https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2025-3877.json
https://api.first.org/data/v1/epss?cve=CVE-2025-3877
https://bugzilla.mozilla.org/show_bug.cgi?id=1958580
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2025-3877
https://www.mozilla.org/security/advisories/mfsa2025-34/
https://www.mozilla.org/security/advisories/mfsa2025-35/
2366291 https://bugzilla.redhat.com/show_bug.cgi?id=2366291
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:*
CVE-2025-3877 https://nvd.nist.gov/vuln/detail/CVE-2025-3877
mfsa2025-34 https://www.mozilla.org/en-US/security/advisories/mfsa2025-34
mfsa2025-35 https://www.mozilla.org/en-US/security/advisories/mfsa2025-35
RHSA-2025:8196 https://access.redhat.com/errata/RHSA-2025:8196
RHSA-2025:8203 https://access.redhat.com/errata/RHSA-2025:8203
RHSA-2025:8324 https://access.redhat.com/errata/RHSA-2025:8324
RHSA-2025:8325 https://access.redhat.com/errata/RHSA-2025:8325
RHSA-2025:8326 https://access.redhat.com/errata/RHSA-2025:8326
RHSA-2025:8391 https://access.redhat.com/errata/RHSA-2025:8391
RHSA-2025:8507 https://access.redhat.com/errata/RHSA-2025:8507
RHSA-2025:8594 https://access.redhat.com/errata/RHSA-2025:8594
RHSA-2025:8756 https://access.redhat.com/errata/RHSA-2025:8756
RHSA-2025:8784 https://access.redhat.com/errata/RHSA-2025:8784
No exploits are available.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:L Found at https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2025-3877.json
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:L Found at https://bugzilla.mozilla.org/show_bug.cgi?id=1958580
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: SSVCv2/E:N/A:N/T:P/P:M/B:A/M:M/D:T/2025-05-15T14:46:32Z/ Found at https://bugzilla.mozilla.org/show_bug.cgi?id=1958580
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:L Found at https://www.mozilla.org/security/advisories/mfsa2025-34/
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: SSVCv2/E:N/A:N/T:P/P:M/B:A/M:M/D:T/2025-05-15T14:46:32Z/ Found at https://www.mozilla.org/security/advisories/mfsa2025-34/
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:L Found at https://www.mozilla.org/security/advisories/mfsa2025-35/
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: SSVCv2/E:N/A:N/T:P/P:M/B:A/M:M/D:T/2025-05-15T14:46:32Z/ Found at https://www.mozilla.org/security/advisories/mfsa2025-35/
Exploit Prediction Scoring System (EPSS)
Percentile 0.02538
EPSS Score 0.00017
Published At May 15, 2025, 12:55 p.m.
Date Actor Action Source VulnerableCode Version
2025-05-14T21:39:26.627725+00:00 Mozilla Importer Import https://github.com/mozilla/foundation-security-advisories/blob/master/announce/2025/mfsa2025-34.yml 36.0.0