Security readout for executives and security teams
Plain-English summary
Fastify versions before 5.7.2 can be tricked into accepting a request body without applying the intended validation rules. For affected public APIs, this can let invalid or unsafe data reach application logic, creating business risk around data integrity and downstream processing.
Executive priority
Prioritize remediation for public or partner-facing Fastify APIs because the bug undermines application validation controls. If Fastify is only used internally with limited trust boundaries, urgency is lower but still appropriate for normal high-severity patch timelines.
Technical view
The issue affects Fastify < 5.7.2. A Content-Type header modified with a tab and extra content can cause body validation schemas selected by Content-Type to be bypassed while parsing still treats the body as the original type. CVSS 7.5 reflects network, unauthenticated exploitation with high integrity impact.
Likely exposure
Exposure is likely in Node.js services running Fastify before 5.7.2, especially APIs that rely on request body schemas for JSON or other typed payload validation. Transitive use through packaged platforms or Red Hat-distributed components should be checked against vendor advisories.
Exploitation context
The provided bundle does not show KEV listing or confirmed active exploitation. Public advisory and HackerOne references indicate the behavior is documented. Treat this as remotely reachable where affected Fastify endpoints accept request bodies, but do not assume exploitation without logs or vendor evidence.
Researcher notes
Focus analysis on parser-versus-validator Content-Type handling. The key question is whether routes depend on Content-Type-specific body schemas. Evidence supports a fixed upstream version, but the bundle does not prove exploitation, affected downstream products beyond listed references, or complete mitigation alternatives.
Mitigation direction
- Upgrade Fastify to version 5.7.2 or later.
- Check Red Hat advisories if Fastify is consumed through Red Hat products.
- Inventory direct and transitive Fastify dependencies across Node.js services.
- Review vendor guidance before applying nonstandard workarounds.
- Prioritize internet-facing APIs that rely on request body validation.
Validation and detection
- Confirm package lockfiles and SBOMs do not contain Fastify < 5.7.2.
- Verify deployed containers or runtimes use the patched dependency version.
- Add regression tests for abnormal Content-Type values and schema enforcement.
- Review API logs for unusual Content-Type headers on body-bearing requests.
- Confirm validation failures still occur for malformed request bodies.
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-179: 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-436: 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-2026-25223 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
- High
- CVSS
- 7.5 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
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:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N3.93.6GitHub_MCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N3.93.6redhat-SADPVulnerability scoring details
Base CVSS 3.1 score
7.5HighVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Base CVSS 3.1 score
7.5HighVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
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
- 2026-02-03T22:01:19.884Z: Reported to Red Hat.
- 2026-02-03T21:21:40.268Z: Made public.
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/fastify/fastify/security/advisories/GHSA-jx2c-rxcm-jvmqCVE reference, GitHub_M · x_refsource_CONFIRM
- https://github.com/fastify/fastify/commit/32d7b6add39ddf082d92579a58bea7018c5ac821CVE reference, GitHub_M · x_refsource_MISC
- https://hackerone.com/reports/3464114CVE reference, GitHub_M · x_refsource_MISC
- https://fastify.dev/docs/latest/Reference/Validation-and-SerializationCVE reference, GitHub_M · x_refsource_MISC
- https://github.com/fastify/fastify/blob/759e9787b5669abf953068e42a17bffba7521348/lib/content-type-parser.js#L125CVE reference, GitHub_M · x_refsource_MISC
- https://github.com/fastify/fastify/blob/759e9787b5669abf953068e42a17bffba7521348/lib/validation.js#L272CVE reference, GitHub_M · x_refsource_MISC
- https://access.redhat.com/security/cve/CVE-2026-25223CVE reference, redhat-SADP · vdb-entry, x_refsource_REDHAT
- RHBZ#2436560CVE reference, redhat-SADP · issue-tracking, x_refsource_REDHAT
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-25223.jsonCVE reference, redhat-SADP · x_sadp-csaf-vex
- https://access.redhat.com/errata/RHSA-2026:5807CVE reference, redhat-SADP · vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:10184CVE reference, redhat-SADP · vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:6192CVE reference, redhat-SADP · vendor-advisory, x_refsource_REDHAT
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.
Incorrect Behavior Order: Early Validation
Incorrect Behavior Order: Early Validation represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.
Interpretation Conflict
Interpretation Conflict represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.