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CVE Record

CVE-2025-8033: Incorrect JavaScript state machine for generators

The JavaScript engine did not handle closed generators correctly and it was possible to resume them leading to a nullptr deref. This vulnerability was fixed in Firefox 141, Firefox ESR 115.26, Firefox ESR 128.13, Firefox ESR 140.1, Thunderbird 141, Thunderbird 128.13, and Thunderbird 140.1.

MediumCVSS 6.5Not KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

A flaw in Mozilla’s JavaScript engine could allow malicious content to resume an already closed generator, causing an invalid memory access. Successful exploitation requires user interaction. The supplied CVSS assessment indicates potential disclosure of sensitive information, although the source bundle does not describe demonstrated data theft or code execution.

Executive priority

Treat this as a normal, time-bound browser and mail-client patching priority. Expedite updates on endpoints exposed to untrusted content or sensitive information. Emergency incident response is not justified by the supplied evidence alone because active exploitation is not documented.

Technical view

The JavaScript generator state machine incorrectly permitted a closed generator to resume, leading to a null-pointer dereference (CWE-476). Mozilla fixed the issue in Firefox 141 and ESR 115.26, 128.13, and 140.1; and Thunderbird 141, 128.13, and 140.1. The CVSS 3.1 score is 6.5 with network reachability, low complexity, no privileges, and required user interaction.

Likely exposure

Exposure is most likely where Firefox or Thunderbird remains below the applicable fixed release. The bundle does not provide complete affected-version ranges, so version comparison should use the organization’s installed release channel and Mozilla advisory. Internet-facing browsing and untrusted message or web content increase practical exposure.

Exploitation context

The supplied record is not in CISA KEV and provides no evidence of active exploitation. The CVSS vector requires user interaction. Public sources describe the underlying null-pointer condition, but the bundle does not establish reliable exploitation, observed attacks, code execution, or a weaponized public exploit.

Researcher notes

The key defect is an invalid transition from a closed generator state to resumed execution, ending in a null-pointer dereference. CVSS claims high confidentiality impact, but the narrative does not explain the disclosure mechanism. Researchers should avoid inferring code execution or broad affected ranges without further vendor evidence.

Mitigation direction

  • Update Firefox to 141 or the applicable ESR release: 115.26, 128.13, or 140.1.
  • Update Thunderbird to 141, 128.13, or 140.1, according to the deployed release channel.
  • Prioritize systems handling untrusted websites, email content, or links.
  • Consult Mozilla or operating-system vendor guidance where package versioning differs.

Validation and detection

  • Inventory Firefox and Thunderbird versions across managed endpoints.
  • Confirm every installation meets its applicable fixed release or vendor backport level.
  • Verify updates completed successfully and browsers or mail clients restarted.
  • Review vulnerability-management results for unmanaged or rarely connected endpoints.
  • Confirm distribution-maintained packages include the vendor security fix.
Prepared
Confidence
high
Sources
11

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cwe · low confidence lookup

CWE-476: Exact CWE lookup

Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

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cve · low confidence lookup

CVE-2025-8033 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

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Vulnerability profileCVE Program record
Severity
Medium
CVSS
6.5 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

1CVSS vectors
3Timeline events
2ADP providers
10Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: noTechnical Impact: partial

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
6.5CVSS 3.1MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N2.83.6CISA-ADP

Vulnerability scoring details

Base CVSS 3.1 score

6.5Medium
CVSS 3.1 vector shape for CVE-2025-8033Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
cvssV3_1other:ssvc
CVECVE Program Container

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
MozillaFirefox115.26, 128.13, 140.1, 141Listed
MozillaThunderbird128.13, 140.1, 141Listed
Weakness

CWE details

CWE-476

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.

CWE-476 · source CWE mapping

NULL Pointer Dereference

NULL Pointer Dereference represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

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