Security readout for executives and security teams
Plain-English summary
Weblate before 5.15.2 could expose uploaded screenshot images because the web server served them without proper access control. An attacker would need to guess screenshot filenames, so the rated severity is low. The main business concern is unintended disclosure of screenshot content, which may include product UI, strings, or context not meant for public access.
Executive priority
Handle through normal patch management unless screenshots contain sensitive material or Weblate is internet-facing. Prioritize internet-exposed or sensitive translation projects, but this is not currently a crisis-level vulnerability based on the provided evidence.
Technical view
CVE-2026-21889 is an improper access control issue in Weblate screenshot delivery. Before version 5.15.2, screenshots were served directly by the HTTP server, allowing access when a filename was guessed. The CVE maps to CWE-284 and has CVSS 4.0 score 2.3. The vendor states the issue is fixed in 5.15.2.
Likely exposure
Organizations running Weblate versions earlier than 5.15.2 are potentially affected, especially if the instance is reachable by untrusted users or the internet. Exposure depends on whether screenshots are used and whether filenames can be guessed.
Exploitation context
The public record describes filename guessing and improper access control. CISA KEV is not indicated, and the provided sources do not report active exploitation or public weaponized exploit availability.
Researcher notes
Evidence is limited to the CVE record, GitHub advisory, pull request, and commit. The issue is access control on static screenshot serving, not code execution. Avoid assuming broader file disclosure beyond screenshots because the provided sources do not support that.
Mitigation direction
- Upgrade Weblate to version 5.15.2 or later.
- Review the GitHub advisory for vendor-specific deployment guidance.
- Restrict untrusted access to Weblate until upgraded, where operationally feasible.
- Review screenshot content for sensitive information exposure.
Validation and detection
- Inventory Weblate instances and confirm running versions.
- Check whether any instance is below 5.15.2.
- Confirm screenshot access is controlled after upgrade.
- Review web access logs for unusual screenshot requests.
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-284: Authorization and privilege behavior lookup
Authorization weaknesses can support privilege escalation and valid-account review, depending on exploit path. 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-2026-21889 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
- Low
- CVSS
- 2.3 (4.0)
- Known Exploited
- No
- Published
Vector: CVSS:4.0/AV:N/AC:H/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:L/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:H/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:L/SI:N/SA:N——Primary CVE scoreVulnerability scoring details
Base CVSS 4.0 score
2.3LowVector: CVSS:4.0/AV:N/AC:H/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:L/SI:N/SA:N
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/WeblateOrg/weblate/security/advisories/GHSA-3g2f-4rjg-9385CVE reference · x_refsource_CONFIRM
- https://github.com/WeblateOrg/weblate/pull/17516CVE reference · x_refsource_MISC
- https://github.com/WeblateOrg/weblate/commit/a6eb5fd0299780eca286be8ff187dc2d10feec47CVE reference · x_refsource_MISC
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 Access Control
Improper Access Control represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.