Unsolicited File Download, Disk Space Exhaustion, and Credential Leakage via mailbox:/// Links
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. This vulnerability was fixed in Thunderbird 128.11.1 and Thunderbird 139.0.2.
- BDU:2025-08579
- ALSA-2025:10195
- ALSA-2025:10196
- ALSA-2025:10246
- DLA-4239-1
- DSA-5959-1
- openSUSE-SU-2025:15204-1
- RHSA-2025:10159
- RHSA-2025:10160
- RHSA-2025:10161
- RHSA-2025:10163
- RHSA-2025:10164
- RHSA-2025:10165
- RHSA-2025:10166
- RHSA-2025:10195
- RHSA-2025:10196
- RHSA-2025:10246
- RLSA-2025:10195
- RLSA-2025:10196
- RLSA-2025:10246
- Published
- Jun 11, 2025
- Updated
- Jun 17, 2026
- EPSS
- 0.6% · 46th percentile
- CWE
- CWE-451
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Report tools
Action score
26
Monitor
Low priority for now.
- CVSS
- 26 / 40 · 6.5 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.6%
CISA SSVC decision
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
Vulnrichment: CISA's decision-tree inputs.
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for the hundreds of thousands of vulnerabilities in the database; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpAffected systems
| Vendor | Product | CPE |
|---|---|---|
| mozilla | thunderbird | cpe:2.3:a:mozilla:thunderbird |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- mozilla thunderbirdbefore 128.11.1
- mozilla thunderbird135.0 and later · before 139.0.2
Versions reported by the vendor
Affected version ranges reported by the assigning authority (mozilla). Independent of NVD's CPE analysis and usually ahead of it.
Mozilla Thunderbird
- 128.11.1 and later · up to and including 128.*not affected · rpm
- 139.0.2 and laternot affected · rpm
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| AlmaLinux:10 | thunderbird | before 128.12.0-1.el10_0.alma.1 | 128.12.0-1.el10_0.alma.1 |
| AlmaLinux:8 | thunderbird | before 128.12.0-1.el8_10.alma.1 | 128.12.0-1.el8_10.alma.1 |
| AlmaLinux:9 | thunderbird | before 128.12.0-1.el9_6.alma.1 | 128.12.0-1.el9_6.alma.1 |
| Debian:11 | thunderbird | before 1:128.12.0esr-1~deb11u1 | 1:128.12.0esr-1~deb11u1 |
| Debian:12 | thunderbird | before 1:128.12.0esr-1~deb12u1 | 1:128.12.0esr-1~deb12u1 |
| Debian:13 | thunderbird | before 1:128.12.0esr-1 | 1:128.12.0esr-1 |
| openSUSE:Tumbleweed | MozillaThunderbird | before 128.11.1-2.1 | 128.11.1-2.1 |
| Red Hat:enterprise_linux:10.0 | thunderbird | before 0:128.12.0-1.el10_0 | 0:128.12.0-1.el10_0 |
| Red Hat:enterprise_linux:10.0 | thunderbird-debuginfo | before 0:128.12.0-1.el10_0 | 0:128.12.0-1.el10_0 |
| Red Hat:enterprise_linux:10.0 | thunderbird-debugsource | before 0:128.12.0-1.el10_0 | 0:128.12.0-1.el10_0 |
| Red Hat:enterprise_linux:8::appstream | thunderbird | before 0:128.12.0-1.el8_10 | 0:128.12.0-1.el8_10 |
| Red Hat:enterprise_linux:8::appstream | thunderbird-debuginfo | before 0:128.12.0-1.el8_10 | 0:128.12.0-1.el8_10 |
| Red Hat:enterprise_linux:8::appstream | thunderbird-debugsource | before 0:128.12.0-1.el8_10 | 0:128.12.0-1.el8_10 |
| Red Hat:enterprise_linux:9::appstream | thunderbird | before 0:128.12.0-1.el9_6 | 0:128.12.0-1.el9_6 |
| Red Hat:enterprise_linux:9::appstream | thunderbird-debuginfo | before 0:128.12.0-1.el9_6 | 0:128.12.0-1.el9_6 |
| Red Hat:enterprise_linux:9::appstream | thunderbird-debugsource | before 0:128.12.0-1.el9_6 | 0:128.12.0-1.el9_6 |
| Red Hat:rhel_aus:8.2::appstream | thunderbird | before 0:128.12.0-1.el8_2 | 0:128.12.0-1.el8_2 |
| Red Hat:rhel_aus:8.2::appstream | thunderbird-debuginfo | before 0:128.12.0-1.el8_2 | 0:128.12.0-1.el8_2 |
| Red Hat:rhel_aus:8.2::appstream | thunderbird-debugsource | before 0:128.12.0-1.el8_2 | 0:128.12.0-1.el8_2 |
| Red Hat:rhel_aus:8.4::appstream | thunderbird | before 0:128.12.0-1.el8_4 | 0:128.12.0-1.el8_4 |
| Red Hat:rhel_aus:8.4::appstream | thunderbird-debuginfo | before 0:128.12.0-1.el8_4 | 0:128.12.0-1.el8_4 |
| Red Hat:rhel_aus:8.4::appstream | thunderbird-debugsource | before 0:128.12.0-1.el8_4 | 0:128.12.0-1.el8_4 |
| Red Hat:rhel_aus:8.6::appstream | thunderbird | before 0:128.12.0-1.el8_6 | 0:128.12.0-1.el8_6 |
| Red Hat:rhel_aus:8.6::appstream | thunderbird-debuginfo | before 0:128.12.0-1.el8_6 | 0:128.12.0-1.el8_6 |
+18
Same product
mozilla: all recordsOther highest-scoring records for the same primary product.
- CVE-2019-11705A flaw in Thunderbird's implementation of iCal causes a stack buffer overflow in icalrecur_add_bydayrules when processing certain email mess42Plan
- CVE-2019-11704A flaw in Thunderbird's implementation of iCal causes a heap buffer overflow in icalmemory_strdup_and_dequote when processing certain email 42Plan
- CVE-2019-11703A flaw in Thunderbird's implementation of iCal causes a heap buffer overflow in parser_get_next_char when processing certain email messages,42Plan
- CVE-2015-2740Buffer overflow in the nsXMLHttpRequest::AppendToResponseText function in Mozilla Firefox before 39.0, Firefox ESR 31.x before 31.8 and 38.x42Plan
- CVE-2013-5603Use-after-free vulnerability in the nsContentUtils::ContentIsHostIncludingDescendantOf function in Mozilla Firefox before 25.0, Firefox ESR 42Plan
- CVE-2013-1719Multiple unspecified vulnerabilities in the browser engine in Mozilla Firefox before 24.0, Thunderbird before 24.0, and SeaMonkey before 2.242Plan
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| almalinux:thunderbird | 128.12.0-1.el10_0.alma.1 · AlmaLinux:10 | Package registry (OSV) |
| debian:thunderbird | 1:128.12.0esr-1~deb12u1 · Debian:12 | Package registry (OSV) |
| opensuse:MozillaThunderbird | 128.11.1-150200.8.224.1 · openSUSE:Leap 15.6 | Package registry (OSV) |
| red hat:thunderbird | 0:128.12.0-1.el9_4 · Red Hat:rhel_eus:9.4::appstream | Package registry (OSV) |
| red hat:thunderbird-debuginfo | 0:128.12.0-1.el9_4 · Red Hat:rhel_eus:9.4::appstream | Package registry (OSV) |
| red hat:thunderbird-debugsource | 0:128.12.0-1.el9_4 · Red Hat:rhel_eus:9.4::appstream | Package registry (OSV) |
| rocky linux:thunderbird | 0:128.12.0-1.el10_0 · Rocky Linux:10 | Package registry (OSV) |
| suse:MozillaThunderbird | 128.11.1-150200.8.224.1 · SUSE:Linux Enterprise Module for Package Hub 15 SP6 | Package registry (OSV) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
- CVE-2026-3889286 days apartSpoofing issue in Thunderbird26Monitor
- CVE-2025-352357 days apartUser Interface (UI) Misrepresentation of attachment URL25Monitor
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- No account or password is required.
- A user must open a link or visit a page.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- none
- Integrity
- none
- Availability
- high · the service can be disrupted
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality impact
- None
- Integrity impact
- None
- Availability impact
- High
Weakness class (CWE)
CWE-451 · User Interface (UI) Misrepresentation of Critical InformationCVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
nvd-secondary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Attack patterns (CAPEC)
ATT&CK techniques
- Internal SpearfishingT1534
- PhishingT1566
- Phishing: Spearfishing AttachmentT1566.001
- Phishing: Spearfishing LinkT1566.002
- Phishing: Spearfishing via ServiceT1566.003
- Phishing for InformationT1598
- Phishing for Information: Spearfishing ServiceT1598.001
- Phishing for Information: Spearfishing AttachmentT1598.002
- Phishing for Information: Spearfishing LinkT1598.003
Change log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
- bugzilla.mozilla.org/buglist.cgi?bug_id=1958580%2C1968012
- www.mozilla.org/security/advisories/mfsa2025-49/
- www.mozilla.org/security/advisories/mfsa2025-50/
- lists.debian.org/debian-lts-announce/2025/07/msg00002.html
Vendor advisories and official records. Exploit/PoC links are deliberately left out.