Mozilla developers reported memory safety bugs present in Thunderbird 78.13.0.
Mozilla developers reported memory safety bugs present in Thunderbird 78.13.0. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Thunderbird < 91.1 and Firefox ESR < 91.1.
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 help- Published
- Nov 2, 2021
- Updated
- Jun 17, 2026
- EPSS
- 1.1% · 65th percentile
- CWE
- CWE-787
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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 · 1.1%
Affected systems
| Vendor | Product | CPE |
|---|---|---|
| mozilla | firefox esr | cpe:2.3:a:mozilla:firefox_esr |
| 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 firefox esrbefore 91.1
- mozilla thunderbirdbefore 91.1
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 ESR
- unspecified and later · before 91.1affected
Mozilla Thunderbird
- unspecified and later · before 91.1affected
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| openSUSE:Leap 15.2 | MozillaFirefox | before 91.2.0-lp152.2.67.1 | 91.2.0-lp152.2.67.1 |
| openSUSE:Leap 15.2 | MozillaThunderbird | before 91.4.0-lp152.2.52.1 | 91.4.0-lp152.2.52.1 |
| openSUSE:Leap 15.2 | rust-cbindgen | before 0.19.0-lp152.2.7.1 | 0.19.0-lp152.2.7.1 |
| openSUSE:Leap 15.3 | MozillaFirefox | before 91.2.0-8.54.1 | 91.2.0-8.54.1 |
| openSUSE:Leap 15.3 | MozillaFirefox-branding-SLE | before 91-9.5.1 | 91-9.5.1 |
| openSUSE:Leap 15.3 | MozillaThunderbird | before 91.4.0-8.45.2 | 91.4.0-8.45.2 |
| openSUSE:Leap 15.3 | rust-cbindgen | before 0.19.0-1.9.1 | 0.19.0-1.9.1 |
| SUSE:HPE Helion OpenStack 8 | MozillaFirefox | before 91.1.0-112.71.1 | 91.1.0-112.71.1 |
| SUSE:HPE Helion OpenStack 8 | MozillaFirefox | before 91.9.0-112.104.1 | 91.9.0-112.104.1 |
| SUSE:HPE Helion OpenStack 8 | MozillaFirefox-branding-SLE | before 91-35.6.6 | 91-35.6.6 |
| SUSE:Linux Enterprise High Performance Computing 15-ESPOS | MozillaFirefox | before 91.9.0-150000.150.34.1 | 91.9.0-150000.150.34.1 |
| SUSE:Linux Enterprise High Performance Computing 15-ESPOS | MozillaFirefox | before 91.2.0-3.155.2 | 91.2.0-3.155.2 |
| SUSE:Linux Enterprise High Performance Computing 15-ESPOS | MozillaFirefox-branding-SLE | before 91-4.19.1 | 91-4.19.1 |
| SUSE:Linux Enterprise Module for Desktop Applications 15 SP2 | MozillaFirefox | before 91.2.0-8.54.1 | 91.2.0-8.54.1 |
| SUSE:Linux Enterprise Module for Desktop Applications 15 SP2 | MozillaFirefox-branding-SLE | before 91-9.5.1 | 91-9.5.1 |
| SUSE:Linux Enterprise Server 11 SP4-LTSS | MozillaFirefox | before 78.14.0-78.140.4 | 78.14.0-78.140.4 |
| SUSE:Linux Enterprise Server 11 SP4-LTSS | MozillaFirefox | before 91.2.0-78.143.1 | 91.2.0-78.143.1 |
| SUSE:Linux Enterprise Server 11 SP4-LTSS | MozillaFirefox-branding-SLED | before 91-21.18.1 | 91-21.18.1 |
| SUSE:Linux Enterprise Workstation Extension 15 SP2 | MozillaThunderbird | before 91.4.0-8.45.2 | 91.4.0-8.45.2 |
Same product
mozilla: all recordsOther highest-scoring records for the same primary product.
- CVE-2021-4127An out of date graphics library (Angle) likely contained vulnerabilities that could potentially be exploited.39Monitor
- CVE-2023-6862A use-after-free was identified in the `nsDNSService::Init`.35Monitor
- CVE-2023-25746Memory safety bugs present in Firefox ESR 102.7.35Monitor
- CVE-2020-15669When aborting an operation, such as a fetch, an abort signal may be deleted while alerting the objects to be notified.35Monitor
- CVE-2022-38476A data race could occur in the <code>PK11_ChangePW</code> function, potentially leading to a use-after-free vulnerability.30Monitor
- CVE-2020-6828A malicious Android application could craft an Intent that would have been processed by Firefox for Android and potentially result in a file30Monitor
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 |
|---|---|---|
| opensuse:MozillaFirefox | 91.2.0-lp152.2.67.1 · openSUSE:Leap 15.2 | Package registry (OSV) |
| opensuse:MozillaFirefox-branding-SLE | 91-9.5.1 · openSUSE:Leap 15.3 | Package registry (OSV) |
| opensuse:MozillaThunderbird | 91.4.0-lp152.2.52.1 · openSUSE:Leap 15.2 | Package registry (OSV) |
| opensuse:rust-cbindgen | 0.19.0-lp152.2.7.1 · openSUSE:Leap 15.2 | Package registry (OSV) |
| suse:MozillaFirefox | 78.14.0-78.140.4 · SUSE:Linux Enterprise Server 11 SP4-LTSS | Package registry (OSV) |
| suse:MozillaFirefox-branding-SLE | 91-35.6.6 · SUSE:HPE Helion OpenStack 8 | Package registry (OSV) |
| suse:MozillaFirefox-branding-SLED | 91-21.18.1 · SUSE:Linux Enterprise Server 11 SP4-LTSS | Package registry (OSV) |
| suse:MozillaThunderbird | 91.4.0-8.45.2 · SUSE:Linux Enterprise Workstation Extension 15 SP2 | 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.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
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
- 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
- None
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality impact
- High
- Integrity impact
- High
- Availability impact
- High
Weakness class (CWE)
CWE-787 · Out-of-bounds WriteCVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
nvd-primary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
MITRE has no CAPEC/ATT&CK mapping for this CWE.
Change log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
- bugzilla.mozilla.org/buglist.cgi?bug_id=1723391%2C1723920%2C1724101%2C1724107
- security.gentoo.org/glsa/202202-03
- security.gentoo.org/glsa/202208-14
- www.mozilla.org/security/advisories/mfsa2021-40/
- www.mozilla.org/security/advisories/mfsa2021-41/
Vendor advisories and official records. Exploit/PoC links are deliberately left out.