VulnerabilityDeferred

CVE-2026-58489

Because the state was not properly validated, an attacker could forge a callback URL containing their own valid GitHub OAuth code.

MEDIUM 6.8EPSS 0.17%

Does this matter?

Lower severity and a low EPSS score (0.17%). Track it; it rarely justifies an emergency change on its own.

Description

HedgeDoc is an open source, real-time collaborative markdown notes application. Prior to 1.11.0, the GitHub Gist export flow created an OAuth2 state value but only checked that it was present rather than validating it against the value expected for the user's session. Because the state was not properly validated, an attacker could forge a callback URL containing their own valid GitHub OAuth code. When processing the callback, HedgeDoc used the victim's logged-in session to select which note to export, but the attacker's authorization code to determine which GitHub account received it. As a result, a logged-in victim who clicked a crafted link could export their own private, protected, or limited note directly into a Gist controlled by the attacker. This issue has been fixed in version 1.11.0.

CVSS 4.0: 6.8 MEDIUMCVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:A/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
EPSS: 0.17% probability · 7th percentile
CISA KEV: Not listed
Weakness: CWE-352
Source: security-advisories@github.com

References

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.