Security readout for executives and security teams
Plain-English summary
This flaw lets a remote attacker make Yandex Browser Lite for Android show a misleading address bar, increasing phishing and credential-theft risk. The public record names versions before 21.1.0. It requires user interaction and is not listed as known exploited in KEV.
Executive priority
Prioritize remediation where the app exists on corporate Android devices, especially for users exposed to phishing. If the app is not deployed, document non-exposure and monitor for source updates.
Technical view
CVE-2021-25254 is an address bar spoofing issue in Yandex Browser Lite for Android before 21.1.0. The record maps it to CWE-116 and CVSS 4.0 score 8.2: network attack vector, low complexity, no privileges, and active user interaction required.
Likely exposure
Exposure appears limited to Android devices running Yandex Browser Lite older than 21.1.0. No other Yandex products, platforms, or browser editions are identified in the provided sources.
Exploitation context
The sources support remote spoofing after user interaction, but do not describe public exploit code, observed attacks, or KEV-listed active exploitation. Treat it as phishing-enablement rather than direct device compromise based on available evidence.
Researcher notes
The public bundle is sparse: it confirms product, platform, affected version threshold, CWE, CVSS vector, and vendor reference, but not root cause details, exploit mechanics, or patch notes. Avoid expanding scope beyond Browser Lite for Android.
Mitigation direction
- Inventory Android devices for Yandex Browser Lite installations.
- Update Yandex Browser Lite to 21.1.0 or later where available.
- Remove or replace the app if supported updates cannot be confirmed.
- Check Yandex guidance for any additional vendor-specific remediation.
- Prioritize managed devices used for email, finance, or privileged access.
Validation and detection
- Verify installed app versions through MDM or endpoint inventory.
- Confirm no managed device runs Yandex Browser Lite before 21.1.0.
- Review mobile browser allowlists for outdated or unmanaged browsers.
- Monitor CVE and vendor pages for revised affected-version guidance.
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-116: 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-2021-25254 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
- 8.2 (4.0)
- Known Exploited
- No
- Published
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:N/VA:N/SC:H/SI:N/SA: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:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N——Primary CVE scoreVulnerability scoring details
Base CVSS 4.0 score
8.2HighVector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N
Source materials
- CVE List V5 sourceCVE List V5
- https://yandex.com/bugbounty/i/hall-of-fame-browser/CVE reference
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 Encoding or Escaping of Output
Improper Encoding or Escaping of Output represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.