Cyber Resilience

CVE-2026-27780

Access Control

Access Control
Published
03 July 2026
Modified
06 July 2026
CVSS Score v3.1 9.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.0047 38th percentile
Risk Priority 70 floored blend · peak EPSS

Summary

CVE-2026-27780 is a critical-severity Incorrect Authorization (CWE-863) vulnerability. Its CVSS base score is 9.8 (Critical).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 38th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to AC-3 (Access Enforcement) and SI-10 (Information Input Validation) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

A01:2025 Broken Access Control

EU & UK References

Vulnerability Data

Gitea versions before 1.26.0 do not fail closed on bufio.Scanner errors while processing pre-receive hook input, allowing oversized input to bypass branch-protection checks.

CWE(s)
CWE-863

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
attack.mitre.org →
Why these techniques?

CVE enables direct exploitation of Gitea (public-facing Git service) via authorization bypass (CWE-863) in branch protection logic.

Confidence: MEDIUM · MITRE ATT&CK Enterprise v19.0

CVEs Like This One

CVE-2026-63733Shared CWE-863
CVE-2025-30743Shared CWE-863
CVE-2026-4262Shared CWE-863
CVE-2026-6343Shared CWE-863
CVE-2026-32228Shared CWE-863
CVE-2026-47998Shared CWE-863
CVE-2026-10106Shared CWE-863
CVE-2026-34364Shared CWE-863
CVE-2026-23984Shared CWE-863
CVE-2026-34506Shared CWE-863

Affected Assets

—
Gitea
inferred from references and description; NVD did not file a CPE for this CVE

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)
  • AC-3 Access Enforcement
  • SI-10 Information Input Validation
  • SI-11 Error Handling
Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)
  • 5 hardening rules · 3 OS baselines
Validate
Prove the fix (OWASP ASVS)

—

Mitigating Controls (NIST 800-53 r5) AI

AC-3 Access Enforcement good match
prevent

Directly enforces branch-protection authorization checks; the CVE is an authorization bypass (CWE-863) when those checks are not applied.

SI-10 Information Input Validation good match
prevent

Requires validation of pre-receive hook input size and structure so that oversized data cannot trigger scanner errors that skip authorization.

SI-11 Error Handling partial match
prevent

Mandates safe error handling that fails closed, preventing the scanner-error path from silently bypassing branch-protection enforcement.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.AA-05 mostly match
prevents

Defining, enforcing, and reviewing access authorizations and least privilege directly prevents incorrect authorization checks.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.5.15 Access control partial match
prevents

Requiring consistency between access rights and classification plus formal approval steps ensures that the authorization logic correctly distinguishes between entities that should and should not be granted access.

A.5.18 Access rights partial match
prevents

Enforcing policy-driven approval and role-change reviews stops incorrect or stale authorization decisions from remaining in effect after job changes or terminations.

A.8.3 Information access restriction partial match
prevents

By tying access rights to identity, device, location and classification, the control reduces the likelihood that an authorization decision will be based on an incorrect or bypassed policy.

References