Security readout for executives and security teams
Plain-English summary
Wire Server allowed too many Wire subdomains to make browser requests with a user’s session cookie. If an attacker also found XSS on any trusted Wire subdomain, they could use that browser session to read sensitive Wire API data. The issue is medium severity because it depends on another vulnerability and user interaction.
Executive priority
Treat as a moderate-priority confidentiality risk. It does not indicate known active exploitation, but it can turn an XSS flaw on a related subdomain into access to sensitive Wire API data through users’ sessions.
Technical view
Before wire-server 2.106.0, nginz set Access-Control-Allow-Origin for all .wire.com subdomains, including wire.com. This broad CORS trust could let XSS on one trusted subdomain issue cookie-authenticated Wire API requests. Sources describe confidentiality impact only, with CVSS 3.1 score 5.7 and vector AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:N/A:N.
Likely exposure
Exposure is limited to wireapp wire-server versions earlier than 2.106.0 with nginz CORS behavior that trusts all .wire.com subdomains. Risk is most relevant where cookie-authenticated Wire API access is possible from broadly trusted origins.
Exploitation context
The provided sources do not show active exploitation and the CVE is not listed as KEV. Exploitation requires a separate XSS vector on a trusted subdomain plus a user session, so this is a chaining risk rather than a standalone direct compromise.
Researcher notes
Key evidence is the GitHub advisory and CVE record. The advisory states no patch exists but gives a workaround: narrow CORS origins to applications that actually need cookies. Do not assess this as exploitable without confirming broad CORS trust and a viable XSS path.
Mitigation direction
- Review vendor advisory guidance for CVE-2021-41101.
- Limit Access-Control-Allow-Origin to apps requiring cookies only.
- Restrict trusted origins to account-pages, team-settings, and webapp where applicable.
- Move away from affected wire-server versions below 2.106.0 where feasible.
- Prioritize XSS prevention and remediation across trusted Wire subdomains.
Validation and detection
- Inventory wire-server versions and flag any below 2.106.0.
- Inspect nginz CORS configuration for overly broad .wire.com origin trust.
- Check API responses for Access-Control-Allow-Origin behavior from approved origins.
- Confirm only cookie-requiring applications receive cookie-capable CORS access.
- Review trusted subdomains for unresolved XSS findings.
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 lookupCVE-2021-41101 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
- 5.7 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:N/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.
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:L/PR:L/UI:R/S:U/C:H/I:N/A:N2.13.6Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
5.7MediumVector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:N/A:N
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/wireapp/wire-server/security/advisories/GHSA-v7xx-cx8m-g66pCVE 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.
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.