CVE-2026-59102 forgejo CVE debrief

Who should care

Defenders responsible for Forgejo instances should assess exposure and apply patches or mitigations to prevent exploitation of this vulnerability. This includes verifying instance configurations, enabling appropriate security measures, and monitoring for suspicious activity related to Actions runs. Security teams should prioritize patching or mitigating this vulnerability to protect against potential JavaScript execution in users' browsers.

Why it matters

CVE-2026-59102 is a stored cross-site scripting vulnerability in Forgejo before version 15.0.3 that allows authenticated attackers to execute arbitrary JavaScript in other users' browsers. Defenders should prioritize verifying exposure and applying patches or mitigations to prevent exploitation.

• Execution of arbitrary JavaScript in users' browsers
• Potential for phishing or further exploitation
• Required verification of Forgejo instance exposure
• Prioritization of patching or mitigation efforts

Technical summary

The vulnerability exists in Forgejo before version 15.0.3 and is triggered when an authenticated attacker sets a full name containing an HTML payload and triggers an Actions run. The DEFAULT_SHOW_FULL_NAME option must be enabled for exploitation to occur. This allows attackers to execute arbitrary JavaScript in users' browsers when they view the affected Actions run page. The vulnerability requires an authenticated attacker and specific configuration to be exploited, impacting users who view the Actions run description.

Defensive priority

Defenders should prioritize verifying exposure and applying patches or mitigations to prevent exploitation of this vulnerability in Forgejo instances.

Recommended defensive actions

• Verify Forgejo instances for exposure to this vulnerability
• Apply patches or mitigations to prevent exploitation
• Monitor for suspicious Actions run activity
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The CVE record and NVD entry provide details about the vulnerability, including its existence in Forgejo before version 15.0.3 and the conditions required for exploitation. Evidence is limited to public CVE and NVD information. Defenders should verify exposure using official channels and apply patches or mitigations accordingly. Additional verification steps may be necessary based on specific environment configurations.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.