Evidence used
- No CISA KEV confirmation is currently recorded.
- EPSS is 0.63% for the current model date.
BlackTreeCVE IntelligenceFull vulnerability report · 2025
CVE-2025-1011High confidence
A bug in WebAssembly code generation could result in a crash
Mozilla · Firefox
8.8HighCVSS 3.1
Within 7 days
Patch availableHigh technical severity; prioritise exposed affected systems while verifying vendor guidance.
R
Open reassessment dashboard →Operational reassessment
Published severity in operational context
Published severityHigh→Operational priority:High, unchanged from published severity.unchanged
Compensating controls
- Validate the affected product branch and deploy the verified fixed release.
- Restrict the affected network interface to trusted sources where business-safe.
- Monitor vendor guidance and exploitation sources for a material change.
Verification
- Confirm that the asset runs Mozilla Firefox and falls inside the recorded affected range.
- Verify the installed build against the product-specific fixed version after deployment.
- Validate exposure, authentication requirements and compensating controls in the actual environment.
- Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Distribution package intelligence
11 package statesRelease-specific package status
Debian, ubuntu findings are scoped to the named distribution, release and source package. An absent finding does not mean a package is unaffected.
Repository candidate not checked
A published vendor fix does not prove that a matching update is enabled and installable on a particular asset. Confirm the local package candidate before scheduling remediation.
| Distribution release | Source package | Vendor state | Fixed version | Evidence |
|---|---|---|---|---|
| Debian trixietrixie · source | firefox-esr | Vendor fix publishedDebian records a fixed source-package version for this release. | 128.7.0esr-1 | Debian Security Tracker ↗Source updated 5 Oct 2026 |
| Debian trixietrixie · source | thunderbird | Vendor fix publishedDebian records a fixed source-package version for this release. | 1:128.7.0esr-1 | Debian Security Tracker ↗Source updated 5 Oct 2026 |
| Debian bookwormbookworm · source | firefox-esr | Vendor fix publishedDebian records a fixed source-package version for this release. | 128.7.0esr-1~deb12u1 | Debian Security Tracker ↗Source updated 5 Oct 2026 |
| Debian bookwormbookworm · source | thunderbird | Vendor fix publishedDebian records a fixed source-package version for this release. | 1:128.7.0esr-1~deb12u1 | Debian Security Tracker ↗Source updated 5 Oct 2026 |
| Debian forkyforky · source | firefox-esr | Vendor fix publishedDebian records a fixed source-package version for this release. | 128.7.0esr-1 | Debian Security Tracker ↗Source updated 5 Oct 2026 |
| Debian forkyforky · source | thunderbird | Vendor fix publishedDebian records a fixed source-package version for this release. | 1:128.7.0esr-1 | Debian Security Tracker ↗Source updated 5 Oct 2026 |
| Debian sidsid · source | firefox | Vendor fix publishedDebian records a fixed source-package version for this release. | 135.0-1 | Debian Security Tracker ↗Source updated 5 Oct 2026 |
| Debian sidsid · source | firefox-esr | Vendor fix publishedDebian records a fixed source-package version for this release. | 128.7.0esr-1 | Debian Security Tracker ↗Source updated 5 Oct 2026 |
| Debian sidsid · source | thunderbird | Vendor fix publishedDebian records a fixed source-package version for this release. | 1:128.7.0esr-1 | Debian Security Tracker ↗Source updated 5 Oct 2026 |
| Ubuntu 24.04 LTSnoble · standard archive | mozjs102 | Under evaluationCanonical reports that the package might be affected and still needs evaluation or fixing. | Not published in this feed | Canonical Ubuntu Security ↗Source updated 5 Oct 2026 |
| Ubuntu 24.04 LTSnoble · standard archive | mozjs115 | Under evaluationCanonical reports that the package might be affected and still needs evaluation or fixing. | Not published in this feed | Canonical Ubuntu Security ↗Source updated 5 Oct 2026 |
High technical severity; prioritise exposed affected systems while verifying vendor guidance.
Patch available01
What, why and how
A bug in WebAssembly code generation could have lead to a crash. It may have been possible for an attacker to leverage this to achieve code execution. This vulnerability was fixed in Firefox 135, Firefox ESR 128.7, Thunderbird 128.7, and Thunderbird 135.
What
A bug in WebAssembly code generation could have lead to a crash. It may have been possible for an attacker to leverage this to achieve code execution. This vulnerability was fixed in Firefox 135, Firefox ESR 128.7, Thunderbird 128.7, and Thunderbird 135.
Why
Untrusted data can cross into a code-evaluation path and be interpreted as executable instructions.
How
An attacker operating through a network path may attempt exploitation without authentication after a user interaction. If successful, the issue may disrupt the affected service.
What
A bug in WebAssembly code generation could have lead to a crash. It may have been possible for an attacker to leverage this to achieve code execution. This vulnerability was fixed in Firefox 135, Firefox ESR 128.7, Thunderbird 128.7, and Thunderbird 135.
Why
Untrusted data can cross into a code-evaluation path and be interpreted as executable instructions.
How
An attacker operating through a network path may attempt exploitation without authentication after a user interaction. If successful, the issue may disrupt the affected service.
02
Exploit reality and attack path
CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.
Observed exploitation No confirmed evidence
?
Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.
Public PoC / exploit material None recorded
?
Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.
- Likely attack path
- a network path → Improper Control of Generation of Code ('Code Injection') → disrupt the affected service
- Attack surface
- Network
- Privileges required
- None: unauthenticated exploitation is possible
- User interaction
- Required interaction required
- Attack complexity
- Low: no specialised conditions are recorded
- Security boundary
- Unchanged: impact remains within the vulnerable component's security authority
- Weakness
?
CWE means Common Weakness Enumeration: a standard category for the underlying weakness. - CWE-94 ↗
CWE-94: Improper Control of Generation of Code ('Code Injection'). The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.
- CVSS vector
?
CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity. CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:HCommon Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.
AVNetworkAttack vector: The vulnerable component can be reached over a network.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRNonePrivileges required: The attacker does not need an account or existing privileges.UIRequiredUser interaction: Another user must perform an action for exploitation to succeed.SUnchangedScope: The security impact remains within the vulnerable component's authority.CHighConfidentiality impact: A successful attack can cause a major loss.IHighIntegrity impact: A successful attack can cause a major loss.AHighAvailability impact: A successful attack can cause a major loss.- Post-exploitation / living off the land
- No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.
03
Patch and workaround
Operational remediation based on structured source evidence.
- Status
?
Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change. - Patch available
- Action
- Review the linked authoritative reference and apply the recorded fixed release appropriate to the affected product branch.
- Workaround
- No verified workaround is recorded. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.
04
Evidence and provenance
Published 4 Feb 2025 · Last source change 13 Apr 2026, 14:25 UTC · CWE-94 · Improper Control of Generation of Code ('Code Injection')
CVE recordCVE.org · 5.2
CVSS sourceNIST NVD
EPSS source FIRST · tracked since 2026-08-14
?
The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.European sourceENISA EUVD · EUVD-2025-1966
Product sourceCNA
Remediation sourceCVE/CNA references
CWE sourceCISA ADP
NVD statusNVD modified after enrichment
Missing structured fields: affected versions. Missing data is not evidence of low risk; review the primary advisory.
Material change intelligence
View recent updates ↗What changed after publication
- Affected versionsThe structured affected or fixed version information changed.CNA ↗
- Before
- See the vendor and CVE records for the affected range. · Fixed: 128.7 ≤ 128.*; 135 ≤ *
- After
- See the vendor and CVE records for the affected range. · Fixed: Firefox: 128.7 ≤ 128.*, 135 ≤ *; Thunderbird: 128.7 ≤ 128.*, 135 ≤ *
CVE published
Fixed release or patch reference recorded
Technical terms and abbreviations used in this report
- CVE
- Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
- CVSS
- Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
- EPSS
- Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
- CWE
- Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
- CNA
- CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
- CISA ADP
- Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
- NVD
- National Vulnerability Database: NIST's enrichment service for CVE records.
- CERT / CSIRT
- A computer security incident response team that publishes warnings or coordinates incident response.
- PoC
- Proof of concept: public material that demonstrates or helps reproduce exploitation.
- CSAF
- Common Security Advisory Framework: a machine-readable format for security advisories.
- LoTL
- Living off the land: abuse of legitimate tools or system functions during an attack.