Privilege escalation in Thunderbird Updater
Thunderbird's update mechanism allowed a medium-integrity user process to interfere with the SYSTEM-level updater by manipulating the file-locking behavior. By injecting code into the user-privileged process, an attacker could bypass intended access controls, allowing SYSTEM-level file operations on paths controlled by a non-privileged user and enabling privilege escalation. This vulnerability was fixed in Firefox 138, Firefox ESR 128.10, Firefox ESR 115.23, Thunderbird 138, and Thunderbird 128.10.
- BDU:2025-06662
- ALSA-2025:4443
- ALSA-2025:4458
- ALSA-2025:4460
- ALSA-2025:4797
- ALSA-2025:7428
- ALSA-2025:7506
- ALSA-2025:7507
- openSUSE-SU-2025:15040-1
- openSUSE-SU-2025:15042-1
- openSUSE-SU-2025:15045-1
- RHSA-2025:4443
- RHSA-2025:4458
- RHSA-2025:4460
- RHSA-2025:4751
- RHSA-2025:4752
- RHSA-2025:4753
- RHSA-2025:4756
- RHSA-2025:4797
- RHSA-2025:7428
- Published
- Apr 29, 2025
- Updated
- Sep 30, 2026
- EPSS
- 0.7% · 50th percentile
- CWE
- CWE-22
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Report tools
Action score
35
Monitor
Low priority for now.
- CVSS
- 35 / 40 · 8.8 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.7%
CISA SSVC decision
- Exploitation
- none
- Automatable
- no
- Technical impact
- total
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 | firefox | cpe:2.3:a:mozilla:firefox |
| 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 firefoxbefore 115.23.0
- mozilla firefoxbefore 138.0
- mozilla firefox116.0 and later · before 128.10.0
- mozilla thunderbirdbefore 128.10.0
- mozilla thunderbird129.0 and later · before 138.0
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 Firefox
- 115.23 and later · up to and including 115.*not affected · rpm
- 128.10 and later · up to and including 128.*not affected · rpm
- 138 and laternot affected · rpm
Mozilla Thunderbird
- 128.10 and later · up to and including 128.*not affected · rpm
- 138 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 | firefox | before 128.10.0-1.el10_0 | 128.10.0-1.el10_0 |
| AlmaLinux:10 | thunderbird | before 128.10.0-1.el10_0.alma.1 | 128.10.0-1.el10_0.alma.1 |
| AlmaLinux:8 | firefox | before 128.10.0-1.el8_10.alma.1 | 128.10.0-1.el8_10.alma.1 |
| AlmaLinux:8 | thunderbird | before 128.10.0-1.el8_10.alma.1 | 128.10.0-1.el8_10.alma.1 |
| AlmaLinux:9 | firefox | before 128.10.0-1.el9_6.alma.1 | 128.10.0-1.el9_6.alma.1 |
| AlmaLinux:9 | firefox | before 128.10.0-1.el9_5.alma.1 | 128.10.0-1.el9_5.alma.1 |
| AlmaLinux:9 | firefox-x11 | before 128.10.0-1.el9_6.alma.1 | 128.10.0-1.el9_6.alma.1 |
| AlmaLinux:9 | firefox-x11 | before 128.10.0-1.el9_5.alma.1 | 128.10.0-1.el9_5.alma.1 |
| AlmaLinux:9 | thunderbird | before 128.10.0-1.el9_5.alma.1 | 128.10.0-1.el9_5.alma.1 |
| openSUSE:Tumbleweed | firefox-esr | before 128.10.0-1.1 | 128.10.0-1.1 |
| openSUSE:Tumbleweed | MozillaFirefox | before 138.0-1.1 | 138.0-1.1 |
| openSUSE:Tumbleweed | MozillaThunderbird | before 128.10.0-1.1 | 128.10.0-1.1 |
| Red Hat:enterprise_linux:10.0 | firefox | before 0:128.10.0-1.el10_0 | 0:128.10.0-1.el10_0 |
| Red Hat:enterprise_linux:10.0 | firefox-debuginfo | before 0:128.10.0-1.el10_0 | 0:128.10.0-1.el10_0 |
| Red Hat:enterprise_linux:10.0 | firefox-debugsource | before 0:128.10.0-1.el10_0 | 0:128.10.0-1.el10_0 |
| Red Hat:enterprise_linux:10.0 | thunderbird | before 0:128.10.0-1.el10_0 | 0:128.10.0-1.el10_0 |
| Red Hat:enterprise_linux:10.0 | thunderbird-debuginfo | before 0:128.10.0-1.el10_0 | 0:128.10.0-1.el10_0 |
| Red Hat:enterprise_linux:10.0 | thunderbird-debugsource | before 0:128.10.0-1.el10_0 | 0:128.10.0-1.el10_0 |
| Red Hat:enterprise_linux:8::appstream | firefox | before 0:128.10.0-1.el8_10 | 0:128.10.0-1.el8_10 |
| Red Hat:enterprise_linux:8::appstream | firefox-debuginfo | before 0:128.10.0-1.el8_10 | 0:128.10.0-1.el8_10 |
| Red Hat:enterprise_linux:8::appstream | firefox-debugsource | before 0:128.10.0-1.el8_10 | 0:128.10.0-1.el8_10 |
| Red Hat:enterprise_linux:8::appstream | thunderbird | before 0:128.10.0-1.el8_10 | 0:128.10.0-1.el8_10 |
| Red Hat:enterprise_linux:8::appstream | thunderbird-debuginfo | before 0:128.10.0-1.el8_10 | 0:128.10.0-1.el8_10 |
| Red Hat:enterprise_linux:8::appstream | thunderbird-debugsource | before 0:128.10.0-1.el8_10 | 0:128.10.0-1.el8_10 |
+66
Same product
mozilla: all recordsOther highest-scoring records for the same primary product.
- CVE-2010-3765Mozilla Firefox 3.5.x through 3.5.14 and 3.6.x through 3.6.11, Thunderbird 3.1.6 before 3.1.6 and 3.0.x before 3.0.10, and SeaMonkey 2.x befKEV94Now
- CVE-2019-11708Insufficient vetting of parameters passed with the Prompt:Open IPC message between child and parent processes can result in the non-sandboxeKEV87Now
- CVE-2015-4495The PDF reader in Mozilla Firefox before 39.0.3, Firefox ESR 38.x before 38.1.1, and Firefox OS before 2.2 allows remote attackers to bypassKEV86Now
- CVE-2013-1690Mozilla Firefox before 22.0, Firefox ESR 17.x before 17.0.7, Thunderbird before 17.0.7, and Thunderbird ESR 17.x before 17.0.7 do not properKEV86Now
- CVE-2019-17026Incorrect alias information in IonMonkey JIT compiler for setting array elements could lead to a type confusion.KEV79This week
- CVE-2024-9680An attacker was able to achieve code execution in the content process by exploiting a use-after-free in Animation timelines.KEV76This week
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:firefox | 128.10.0-1.el9_5.alma.1 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:firefox-x11 | 128.10.0-1.el9_5.alma.1 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:thunderbird | 128.10.0-1.el9_5.alma.1 · AlmaLinux:9 | Package registry (OSV) |
| opensuse:firefox-esr | 128.10.0-1.1 · openSUSE:Tumbleweed | Package registry (OSV) |
| opensuse:MozillaFirefox | 128.10.0-150200.152.179.1 · openSUSE:Leap 15.6 | Package registry (OSV) |
| opensuse:MozillaThunderbird | 128.10.0-150200.8.212.1 · openSUSE:Leap 15.6 | Package registry (OSV) |
| red hat:firefox | 0:128.10.0-1.el9_5 · Red Hat:enterprise_linux:9::appstream | Package registry (OSV) |
| red hat:firefox-debuginfo | 0:128.10.0-1.el9_5 · Red Hat:enterprise_linux:9::appstream | Package registry (OSV) |
| red hat:firefox-debugsource | 0:128.10.0-1.el9_5 · Red Hat:enterprise_linux:9::appstream | Package registry (OSV) |
| red hat:firefox-x11 | 0:128.10.0-1.el9_5 · Red Hat:enterprise_linux:9::appstream | Package registry (OSV) |
| red hat:thunderbird | 0:128.10.0-1.el9_5 · Red Hat:enterprise_linux:9::appstream | Package registry (OSV) |
| red hat:thunderbird-debuginfo | 0:128.10.0-1.el9_5 · Red Hat:enterprise_linux:9::appstream | Package registry (OSV) |
| red hat:thunderbird-debugsource | 0:128.10.0-1.el9_5 · Red Hat:enterprise_linux:9::appstream | Package registry (OSV) |
| rocky linux:firefox | 0:128.10.0-1.el9_5 · Rocky Linux:9 | Package registry (OSV) |
| rocky linux:thunderbird | 0:128.10.0-1.el9_5 · Rocky Linux:9 | Package registry (OSV) |
| suse:MozillaFirefox | 128.10.0-112.255.1 · SUSE:Linux Enterprise Server 12 SP5-LTSS | Package registry (OSV) |
| suse:MozillaFirefox | 128.10.0-150200.152.179.1 · SUSE:Linux Enterprise Module for Desktop Applications 15 SP6 | Package registry (OSV) |
| suse:MozillaThunderbird | 128.10.0-150200.8.212.1 · 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-2023-6209525 days apartRelative URLs starting with three slashes were incorrectly parsed, and a path-traversal "/../" part in the path could be used to override th26Monitor
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
- CVE-2025-302928 days apartURL Bar Spoofing via non-BMP Unicode characters29Monitor
- CVE-2025-10530140 days apartSpoofing issue in the WebAuthn component in Firefox for Android26Monitor
- CVE-2025-10531140 days apartMitigation bypass in the Web Compatibility: Tooling component21Monitor
- CVE-2025-2742556 days apartQR code user confirmation bypass with invalid protocol17Monitor
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.
- A low-privileged account is enough.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- high · data can be read
- Integrity
- high · data or configuration can be modified
- Availability
- high · the service can be disrupted
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- High
- Integrity impact
- High
- Availability impact
- High
Weakness class (CWE)
CWE-22 · Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
nvd-secondary
Root cause
A user-supplied file name is joined with the allowed directory, but the result is never checked to confirm it is still inside that directory.
The bug in code
The whole CWE-22 classA representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.
Vulnerable
const file = path.join(ROOT, req.query.name);res.sendFile(file);Fixed
const file = path.resolve(ROOT, req.query.name);if (!file.startsWith(ROOT + path.sep)) { return res.sendStatus(400);}res.sendFile(file);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)
- Path TraversalCAPEC-126likelihood: High · Very High
- Using Slashes and URL Encoding Combined to Bypass Validation LogicCAPEC-64likelihood: High · High
- Manipulating Web Input to File System CallsCAPEC-76likelihood: High · Very High
- Using Escaped Slashes in Alternate EncodingCAPEC-78likelihood: High · High
- Using Slashes in Alternate EncodingCAPEC-79likelihood: High · High
ATT&CK techniques
—
Change log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
- bugzilla.mozilla.org/show_bug.cgi?id=1917536
- www.mozilla.org/security/advisories/mfsa2025-28/
- www.mozilla.org/security/advisories/mfsa2025-29/
- www.mozilla.org/security/advisories/mfsa2025-30/
- www.mozilla.org/security/advisories/mfsa2025-31/
- www.mozilla.org/security/advisories/mfsa2025-32/
- lists.debian.org/debian-lts-announce/2025/05/msg00022.html
Vendor advisories and official records. Exploit/PoC links are deliberately left out.