Security readout for executives and security teams
Plain-English summary
Ratpack applications before 1.9.0 could trust a supplied X-Forwarded-Host value when building redirects. If a caching layer stores that redirect without varying on the header, users may later be sent to an attacker-controlled site. Exposure depends on both Ratpack configuration and cache behavior, especially for internet-facing Ratpack services behind shared caches.
Executive priority
Treat as high priority for public Ratpack services behind shared caches or CDNs. The fix path is clear, but exposure is configuration-dependent. Prioritize confirming affected Ratpack versions, PublicAddress settings, and redirect caching behavior before emergency escalation.
Technical view
The issue is cached redirect poisoning tied to Ratpack's default inferring PublicAddress before 1.9.0. A user-controlled X-Forwarded-Host header can influence redirect generation. When an upstream cache does not include that header in its cache key, the poisoned redirect can be served to other users. Ratpack 1.9.0 patches the behavior; custom PublicAddress configuration is the documented workaround.
Likely exposure
Most likely exposed systems are Ratpack versions below 1.9.0, using the default PublicAddress behavior, behind a caching proxy or CDN whose cache key omits X-Forwarded-Host. Systems with a correctly configured custom PublicAddress or no relevant shared redirect caching are less likely exposed.
Exploitation context
The source bundle does not show known active exploitation, and KEV is false. The attack requires a suitable cache configuration and redirect path, reflected by CVSS high attack complexity. Business impact is mainly misdirection, phishing enablement, integrity loss, and potential availability or confidentiality side effects.
Researcher notes
This maps to CWE-807 because security-relevant behavior depends on untrusted input. The key condition is interaction between Ratpack's inferred PublicAddress and an upstream cache that does not vary on X-Forwarded-Host. Avoid assuming exploitability without confirming both application redirects and cache-key behavior.
Mitigation direction
- Upgrade Ratpack to version 1.9.0 or later.
- Configure ServerConfigBuilder::publicAddress correctly for production deployments.
- Review cache behavior for redirects generated by Ratpack services.
- Ensure vendor guidance is followed where cache or proxy behavior differs.
Validation and detection
- Inventory applications using Ratpack and identify versions below 1.9.0.
- Check whether production uses a custom PublicAddress configuration.
- Review CDN or proxy cache keys for X-Forwarded-Host-sensitive redirects.
- Confirm redirect responses cannot be cached with attacker-influenced host values.
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-807: 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-2021-29479 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 (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:L
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.
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:L2.24.7Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
7HighVector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:L
Source materials
- CVE List V5 sourceCVE List V5
- https://portswigger.net/web-security/web-cache-poisoningCVE reference · x_refsource_MISC
- https://github.com/ratpack/ratpack/security/advisories/GHSA-w6rq-6h34-vh7qCVE reference · x_refsource_CONFIRM
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.
Reliance on Untrusted Inputs in a Security Decision
Reliance on Untrusted Inputs in a Security Decision represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.