Security readout for executives and security teams
Plain-English summary
A specially crafted URL may trigger cross-site scripting when Jastow runs with embedded Undertow and a configuration allowing unescaped URL characters. Successful abuse could let attacker-controlled content affect application integrity and expose limited information. Exploitation requires a specific, non-default-seeming configuration combination, reducing broad exposure.
Executive priority
Treat as a planned, near-term remediation for internet-facing EAP applications. Escalate priority where the enabling URL configuration is confirmed or sensitive workflows could be altered. The moderate rating reflects meaningful integrity risk balanced against high exploitation complexity and configuration dependence.
Technical view
CVE-2025-12799 is a CWE-79 input-handling flaw involving unsanitized URI data in Jastow with embedded Undertow. It is remotely reachable without authentication, but rated high complexity. CVSS 3.1 is 6.5, with low confidentiality impact, high integrity impact, no availability impact, and unchanged scope.
Likely exposure
Exposure is most likely in Red Hat JBoss EAP 8.1 deployments using the listed Jastow or EAP packages, embedded Undertow, and settings permitting unescaped URL characters. Deployments lacking that configuration combination may not be exploitable. The bundle does not identify every enabling setting or fixed package version.
Exploitation context
The source bundle marks this CVE as absent from KEV and provides no evidence of active exploitation. Network access, no privileges, and no user interaction are reflected in the CVSS vector, while high attack complexity reflects the required configuration combination. KEV absence does not prove exploitation has never occurred.
Researcher notes
The affected data explicitly identifies Jastow 2.2.9.SP1-redhat-00001 and numerous EAP 8.1 for RHEL 10 packages. It does not clarify whether every listed package independently contains vulnerable code, nor provide the exact configuration keys, attack mechanics, or fixed versions. Validate against Red Hat advisories before drawing package-level conclusions.
Mitigation direction
- Review the applicable Red Hat advisories and apply vendor-provided EAP or Jastow updates.
- Disable URL settings that permit unescaped characters where application compatibility allows.
- Restrict public access to affected applications until configuration and update status are verified.
- Follow Red Hat guidance for exact fixed builds; the bundle does not supply them.
Validation and detection
- Inventory JBoss EAP 8.1 deployments and the io.undertow.jastow/jastow component version.
- Identify embedded Undertow deployments configured to allow unescaped URL characters.
- Compare installed Red Hat packages against the applicable RHSA advisory update sets.
- Use safe defensive testing to confirm URI data is encoded before browser rendering.
- Review application and proxy logs for suspicious encoded or unescaped URI activity.
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-79: User-session and phishing behavior lookup
Client-side and session-facing weaknesses should be reviewed alongside initial-access and user-execution behaviors. 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 lookupContainer behavior lookup
The affected technology mentions containers, so container-specific ATT&CK technique review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2025-12799 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
- Medium
- CVSS
- 6.5 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/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
1 official scoreWe 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:H/PR:N/UI:N/S:U/C:L/I:H/A:N2.24.2redhatVulnerability scoring details
Base CVSS 3.1 score
6.5MediumVector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- Source timelineredhat
Reported to Red Hat.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- Source timelineredhat
Made public.
- CVE publishedCVE Program
The CVE record was published.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
Source materials
- CVE List V5 sourceCVE List V5
- RHSA-2026:36342CVE reference, redhat · vendor-advisory, x_refsource_REDHAT
- RHSA-2026:36343CVE reference, redhat · vendor-advisory, x_refsource_REDHAT
- RHSA-2026:36344CVE reference, redhat · vendor-advisory, x_refsource_REDHAT
- RHSA-2026:36345CVE reference, redhat · vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/security/cve/CVE-2025-12799CVE reference, redhat · vdb-entry, x_refsource_REDHAT
- RHBZ#2413071CVE reference, redhat · issue-tracking, 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.
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.