CVE-2024-4367
A type check was missing when handling fonts in PDF.js, which would allow arbitrary JavaScript execution in the PDF.js context. This vulnerability affects Firefox < 126, Firefox ESR < 115.11, and Thunderbird < 115.11.
- CVSS
- 8.8High
- Exploited in the wild
- Not knownPublic exploit code; not in CISA KEV
- EPSS
- 70.7%chance of exploitation in the next 30 daystop 0.6% of scored CVEsFIRST score of 11 Nov 2026
- Fix
- Patch availablesee the advisories in the references
- Published
- 14 May 2024analysed here 12 Nov 2026
Summary
Triage
The summary, impact and action text on this page are written by our AI analysis pipeline, or taken from the NVD description when a CVE was imported from NVD. They are not the vendor's wording: check them against the sources. A longer AI executive summary and technical analysis are generated for signed-in accounts on the Max plan.
Affected products
| Product | Affected versions | Vendor says fixed in |
|---|---|---|
| Mozilla Firefox | < 126Vendor says fixed in: not stated | |
| Mozilla Firefox ESR | < 115.11Vendor says fixed in: not stated | |
| Mozilla Thunderbird | < 115.11Vendor says fixed in: not stated |
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.
Products named in our analysis
- mozilla:firefox
- mozilla:thunderbird
- debian:debian_linux
- open-xchange:open-xchange_appsuite_frontend
Fix and mitigation
WAF and other mitigations
Can a WAF block it? Partly. The bug can be reached over the network, so generic WAF rules may stop some attacks. Its weakness type is unknown, so we cannot be more precise.
Also consider: patch
Based on the weakness type only; no CVE-specific evidence yet. We check Cloudflare, AWS, Google Cloud Armor and Azure; for Akamai, Imperva, Fastly, F5, ask your vendor.
Remediation steps (AI-written)
Step-by-step remediation is generated for accounts on the Max plan, for CVEs that match a technology in their stack. Add this technology to your stack to see the fix checklist.
Exploitation evidence
- CISA KEV catalog
- Not listed as of our last sync.
- Public exploit code
- Yes: 1 on Exploit-DB · 30 GitHub proofs of concept
Exploit-DB
- Firefox ESR 115.11 - PDF.js Arbitrary JavaScript executionremote, 22 Apr 2025
GitHub proofs of concept
- LOURC0D3/CVE-2024-4367-PoC203 stars
- s4vvysec/CVE-2024-4367-POC58 stars
- Zombie-Kaiser/cve-2024-4367-PoC-fixed12 stars
- spaceraccoon/detect-cve-2024-436711 stars
and 26 more repositories
Listed so you can judge urgency, not as a recommendation to run anything. GitHub “proofs of concept” are unvetted: some are fake or carry malware. Exploit-DB marks the entries its staff verified.
Timeline
- 14 May 2024Published
- 20 May 2024First public exploit or proof of concept5 days later
- 12 Nov 2026Analysed by vulneraibility.com907 days (about 2 years) later
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
| Metric | Value | What it means |
|---|---|---|
| Attack vector | NetworkReachable over the internet or any routable network. | Reachable over the internet or any routable network. |
| Attack complexity | LowRepeatable attack, no special conditions. | Repeatable attack, no special conditions. |
| Privileges required | NoneThe attacker needs no prior access. | The attacker needs no prior access. |
| User interaction | RequiredA victim must click, open or otherwise cooperate. | A victim must click, open or otherwise cooperate. |
| Scope | UnchangedImpact stays within the vulnerable component. | Impact stays within the vulnerable component. |
| Confidentiality | HighTotal data disclosure possible. | Total data disclosure possible. |
| Integrity | HighComplete modification possible. | Complete modification possible. |
| Availability | HighFull outage possible. | Full outage possible. |
Common questions
Is CVE-2024-4367 being exploited?
Not confirmed. CVE-2024-4367 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 71% probability of exploitation in the next 30 days.
How severe is CVE-2024-4367?
CVE-2024-4367 is rated High with a CVSS score of 8.8. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2024-4367?
Yes. A fix has been recorded for CVE-2024-4367. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2024-4367 affect?
CVE-2024-4367 affects mozilla:firefox, mozilla:thunderbird, debian:debian_linux, open-xchange:open-xchange_appsuite_frontend. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
References
Where the data on this page comes from
- CVE List (CVE.org): description, affected versions, references; CVE Terms of Use
- NVD: CVSS and CPE data
- FIRST EPSS: exploit probability and percentile
- Exploit-DB: published exploits
- PoC-in-GitHub: GitHub repositories that claim a proof of concept
Summary, impact and triage tags: written by our AI analysis pipeline from the sources above. Check them against the sources.
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