CVE-2026-77573: CWE-367: Time-of-check Time-of-use (TOCTOU) Race Condition in WeblateOrg weblate
Description
CVE-2026-77573 is a time-of-check to time-of-use (TOCTOU) race condition vulnerability in Weblate versions prior to 2026.8. It allows a user with permission to manage component repository URLs to perform server-side request forgery (SSRF) against internal services via DNS rebinding during version control system (VCS) operations. The vulnerability arises because Weblate validates the hostname's initial DNS resolution but the external VCS clients perform a separate DNS lookup later, enabling an attacker-controlled hostname to be redirected to internal or private addresses. This can lead to unauthorized access to internal VCS-compatible services and potential exposure of private repository contents. The issue affects installations that allow untrusted repository hostnames while using the VCS_RESTRICT_PRIVATE=True setting. The vulnerability is fixed in Weblate version 2026.8.
CVSS v3.1
Score 3.5low
Affected software
WeblateOrg
weblate
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
This vulnerability in Weblate is a TOCTOU race condition involving DNS rebinding during VCS operations. Weblate initially validates the hostname's DNS resolution, but the external VCS client performs a separate DNS lookup when connecting. An attacker can exploit this by controlling a hostname that first resolves to a public IP and then to an internal IP, causing Weblate to connect to internal services unintentionally. This can result in server-side request forgery to internal VCS-compatible services and potential exposure of private repository data. The vulnerability affects configurations permitting untrusted repository hostnames with VCS_RESTRICT_PRIVATE=True. The issue is resolved in version 2026.8.
Potential Impact
An attacker with permission to manage component repository URLs can exploit this vulnerability to perform SSRF attacks against internal services by leveraging DNS rebinding. This may lead to unauthorized access to internal VCS-compatible services and potential exposure of private repository contents. The CVSS score is 3.5 (low severity), indicating limited impact primarily on confidentiality with no integrity or availability impact.
Mitigation Recommendations
This vulnerability is fixed in Weblate version 2026.8. Users should upgrade to version 2026.8 or later to remediate this issue. Until upgrading, installations should avoid permitting untrusted repository hostnames when using VCS_RESTRICT_PRIVATE=True. No other vendor advisory or patch information is available, so check the vendor advisory for any updates.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-08-20T20:35:30.147Z
- Cvss Version
- 3.1
- State
- PUBLISHED
Threat ID: 6a8f55a2acd9273b496333d7
Added to database: 08/26/2026, 21:07:46 UTC
Last enriched: 09/10/2026, 09:53:53 UTC
Last updated: 10/10/2026, 06:48:19 UTC
Views: 109
Community Reviews
0 reviewsCrowdsource mitigation strategies, share intel context, and vote on the most helpful responses. Sign in to add your voice and help keep defenders ahead.
Want to contribute mitigation steps or threat intel context? Sign in or create an account to join the community discussion.
Actions
Updates to AI analysis require Pro Console access. Upgrade inside Console → Billing.
Need more coverage?
Upgrade to Pro Console for AI refresh and higher limits.
For incident response and remediation, OffSeq services can help resolve threats faster.
Latest Threats
Check if your credentials are on the dark web
Instant breach scanning across billions of leaked records. Free tier available.