Gitea: WebAuthn second factor bypass in OAuth2 and OpenID Connect sign-in
Summary
Gitea versions 1.16.0 up to and including 1.27.1 do not enforce the WebAuthn challenge on OAuth2 and OpenID Connect sign-in when WebAuthn is the account's only second factor (no TOTP). An attacker who can authenticate through the affected external identity flow can obtain a full session without the passkey check that applies to password login. On the account-link path, the attacker can also permanently bind their external identity to the victim's Gitea account, so access may persist after a password change.
Affected
- Gitea 1.16.0 up to and including 1.27.1
- Only accounts with WebAuthn as sole second factor (no TOTP) and OAuth2/OpenID Connect sign-in enabled
- Default configuration: unaffected
Fixed in
- Gitea 1.27.2 (released 14 August 2026)
Workaround
Unknown.
Exploitation
- No known exploitation at the time of the sources reviewed; CISA SSVC lists exploitation as none and automatable as yes.
- No public proof of concept found.
Our recommendation
- Upgrade Gitea to 1.27.2 or later as soon as possible.
- Until upgraded, disable OAuth2/OpenID Connect sign-in if it is not needed.
- Review accounts that use only a passkey or security key as second factor and check for unexpected external identity links.
- Restrict exposure of self-hosted instances that are reachable from the internet.
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- Gitea 1.27.2 release notes blog.gitea.com
- Gitea v1.27.2 release github.com
- GitHub Security Advisory GHSA-92j2-6qcg-c28c github.com
- Fix PR #38805 github.com
- Fix PR #38810 github.com
- OSV entry CVE-2026-73278 osv.dev
- Gitea Cloud 1.27.3 release notice about.gitea.com
Researched and written up in English and German by an AI (Claude by Anthropic) based on NVD, CISA, EPSS and the sources listed. The vendor information is authoritative. Researched on 30 Oct 2026, 21:01.
Original description (NVD)
Gitea's OAuth2 and OpenID Connect sign-in paths do not require a WebAuthn challenge when WebAuthn is the account's only configured second factor. A party able to authenticate through the affected external identity flow can obtain a full session without the passkey verification enforced during password login. One affected path can also persist an external identity link, extending the compromise beyond the initial session; accounts with TOTP configured are outside the reported WebAuthn-only scenario.
Sources
The tracker combines official, freely usable data sources – updated continuously:
- NVD (NIST) – CVEs, rating (CVSS), affected products
- CISA KEV – vulnerabilities confirmed by CISA as actively exploited
- CISA Vulnrichment – CISA assessment (SSVC) in the official CVE record
- FIRST EPSS – probability of exploitation
- Microsoft MSRC – Patch Tuesday: vulnerabilities, severity, updates
- PoC-in-GitHub – public proof-of-concept repositories
- Metasploit (Rapid7) – modules of the Metasploit Framework
- Exploit-DB (OffSec) – archive of public exploits (links only)
- Patch days: official vendor pages (linked per vendor) (Vendor patch days)
This product uses data from the NVD API but is not endorsed or certified by the NVD. EPSS data © FIRST.org.
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