CVE-2026-26247: Gitea versions before 1.25.5 do not persist the OAuth2 PKCE S256 challenge method correctly during authorization, allowing token exchange without the expected verifier check.

criticalCVSS 9.1CVE-2026-26247

Gitea versions before 1.25.5 do not persist the OAuth2 PKCE S256 challenge method correctly during authorization, allowing token exchange without the expected verifier check.

Details

Source: NVD Recent CVEs (US · database · site)
Severity: critical — CVSS 9.1
Published: 2026-07-03
Last updated: 2026-07-07
Exploitation: Not in CISA KEV at last sync

Original advisory: https://nvd.nist.gov/vuln/detail/CVE-2026-26247

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Low exploitation riskCVE-2026-262470.38% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 30% of all scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-26247	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.

medium[UPDATE] [medium] Gitea: Multiple vulnerabilitiescert-bund

Recent advisories for Gitea

A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.

high[UPDATE] [high] Gitea: Vulnerability allows bypassing of security measurescert-bund · 2026-07-09
medium[UPDATE] [medium] Gitea: Multiple vulnerabilitiescert-bund · 2026-07-08
high[UPDATE] [high] Gitea: Multiple vulnerabilitiescert-bund · 2026-07-06
high[UPDATE] [high] Gitea: Multiple vulnerabilitiescert-bund · 2026-07-06
high[UPDATE] [high] Gitea: Multiple vulnerabilitiescert-bund · 2026-07-06
medium[UPDATE] [medium] Gitea: Multiple vulnerabilitiescert-bund · 2026-07-06