Gitea OAuth2 account auto-linking takeover through the sign-up form
- Exploited
- No known exploitation
- Fix
- Fixed in 28.3.0
- Who is exposed
- Not reported
Do first: Upgrade to a fixed version: 28.3.0.
- Last modified
- FIRST's estimate of the chance attackers exploit it in the next 30 days, updated daily.What do these mean? →
- 0.34% · 28th percentile
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 30/100
- How many real-world setups can hit the bug, from the vendor's advisory and CISA data. It does not know your setup.What do these mean? →
- Unclear
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
- Exploitation: none
- Automatable: yes
- Technical impact: total
Summary
Gitea, the self-hosted Git service, is affected when its OAuth2 account auto-linking option is enabled alongside open registration. An attacker with an account on a configured OAuth2 provider could take over another user's Gitea account, including an administrator account, without knowing its password, and the takeover would persist for later sign-ins.
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
Read the original description
When [oauth2_client].ACCOUNT_LINKING is set to auto (not the default) and registration is enabled, the link-account sign-up form looked up the existing account to link by the user name or email submitted in the form instead of the identity asserted by the OAuth2 provider. An attacker with an account on a configured OAuth2 provider could submit another user's name, link their external identity to that Gitea account and be signed in as it without its password, including as an administrator. The link persisted for later sign-ins. Automatic linking now only happens when the existing account matches the provider's email or provider-derived user name; otherwise the account password is required.
cve.now Index
- Exploitation0/40No signal
- Exposure20/25No login or user action needed, CISA rates it automatable · Unknown: Advisories don't say whether default setups are affected
- Reach?/20Unknown. No tracked technology or package matched
- Severity10/10CVSS 9.8, total technical impact per CISA
- No patch0/5No signal
What would change the score
- Would score about 75 if added to CISA KEV
- Would score about 70 if CISA's SSVC rates exploitation active
- Would score about 35 if advisories confirm default setups are exposed
What to do
Upgrade to a fixed version: 28.3.0.
Timeline
- CVE published
- First seen by cve.now5 days
- CISA SSVC assessment
Exploitation: none · Automatable: yes · Technical impact: total
- Record last updated
- Posted on X by cve.now
Affected versions
- gitea.dev
fixed in 28.3.0
Evidence 5
- Advisory
- Patch
- Patch
- Repository
- Link
Corrections
None so far.
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Questions about CVE-2026-120263
Is CVE-2026-120263 being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data
Which versions are affected by CVE-2026-120263?
gitea.dev: before 28.3.0.Source: cve.now feed data
How do I fix CVE-2026-120263?
Upgrade Gitea to version 28.3.0 or later, which contains the fix. The checked facts list no workaround, so upgrading is the only documented remedy.Source: github.com