Security readout for executives and security teams
Plain-English summary
A vulnerable Locutus JavaScript dependency can let malicious input alter shared object behavior inside an application. That can undermine application logic and potentially affect data confidentiality, integrity, and availability. The issue is critical, but the supplied sources do not show active exploitation.
Executive priority
Prioritize remediation this cycle for any production application using the affected package range. The business risk is dependency-driven: if Locutus is absent, exposure is unlikely; if present in input-facing services, patch quickly because object-level pollution can break trust boundaries.
Technical view
Locutus versions 2.0.12 through before 2.0.39 are affected by prototype pollution. A prior forbidden-key check was incomplete, allowing Object.prototype pollution through crafted input using String.prototype. The advisory maps this to CWE-1321 and CWE-915 and assigns CVSS 4.0 score 9.4. Version 2.0.39 patches it.
Likely exposure
Exposure is most likely in JavaScript applications or packages using locutus >=2.0.12 and <2.0.39, especially where untrusted input reaches affected Locutus functionality. Transitive dependency use should also be checked. The bundle does not identify affected downstream products beyond locutus itself.
Exploitation context
The source bundle says exploitation uses crafted input and String.prototype to pollute Object.prototype. KEV is false, and no cited source in the bundle confirms active exploitation in the wild. Treat internet-facing or input-heavy applications as higher priority until dependency exposure is ruled out.
Researcher notes
The evidence is strong for affected versions, weakness class, CVSS, and fixed version. The bundle does not provide exploit telemetry, affected downstream packages, or detailed vulnerable function mapping. Avoid assuming remote exploitability beyond application-specific data flow into Locutus.
Mitigation direction
- Upgrade locutus to version 2.0.39 or later.
- Regenerate and review lockfiles after dependency updates.
- Check vendor advisories for any additional product-specific guidance.
- Prioritize applications processing untrusted input through Locutus-dependent code.
- Monitor CVE and GHSA pages for exploitation or remediation updates.
Validation and detection
- Search package manifests and lockfiles for locutus versions.
- Use SCA tooling to detect direct and transitive locutus dependency paths.
- Confirm deployed artifacts no longer include versions 2.0.12 through 2.0.38.
- Review code paths that pass user-controlled input into Locutus functionality.
- Run regression tests covering prototype-pollution protections after upgrade.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
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-1321: 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.
Open ATT&CK lookupCWE-915: 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.
Open ATT&CK lookupCVE-2026-25521 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Critical
- CVSS
- 9.4 (4.0)
- Known Exploited
- No
- Published
Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
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.
SSVC decision data
CVSS vector scores
2 official scoresWe 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.
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H——GitHub_MCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H2.56redhat-SADPVulnerability scoring details
Base CVSS 4.0 score
9.4CriticalVector: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
Base CVSS 3.1 score
9.3CriticalVector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- ADP timelineredhat-SADP
Made public.
- CVE publishedCVE Program
The CVE record was published.
- ADP timelineredhat-SADP
Reported to Red Hat.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
- 2026-02-04T22:01:35.989Z: Reported to Red Hat.
- 2026-02-04T21:20:32.643Z: Made public.
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/locutusjs/locutus/security/advisories/GHSA-rxrv-835q-v5mhCVE reference, GitHub_M · x_refsource_CONFIRM
- https://github.com/locutusjs/locutus/commit/042af9ca7fde2ff599120783e720a17f335bb01cCVE reference, GitHub_M · x_refsource_MISC
- https://access.redhat.com/security/cve/CVE-2026-25521CVE reference, redhat-SADP · vdb-entry, x_refsource_REDHAT
- RHBZ#2436950CVE reference, redhat-SADP · issue-tracking, x_refsource_REDHAT
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-25521.jsonCVE reference, redhat-SADP · x_sadp-csaf-vex
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')
Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.
Improperly Controlled Modification of Dynamically-Determined Object Attributes
Improperly Controlled Modification of Dynamically-Determined Object Attributes represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.