Vulnerability report

Active exploitation observed Confirmed confidence Not in CISA KEV

CVE-2026-20896

Gitea Docker image trusts spoofable reverse-proxy headers by default

Gitea Open Source Git Server · 0 to <= 1.26.2

Watch CVE-2026-20896 Browse KEV feed
Severity
CVSS 9.8 · Critical
Confidence
Confirmed
Exploit status
Observed in sensors
EPSS
2.8%
First observed
20 Oct 2026
Last observed
21 Oct 2026

Decision summary

What security teams need to know first

Direct answers before the deeper technical record.

What it is

CVE-2026-20896 is an unauthenticated Gitea Docker image trusts spoofable reverse-proxy headers by default.

Is it exploited?

Yes. Previdian sensors observed exploitation attempts with confirmed confidence.

Who is affected?

Gitea Open Source Git Server 0 to <= 1.26.2.

What should we do?

Patch immediately, validate internet-facing exposure, and monitor for matching requests.

Overview

Gitea Docker image trusts spoofable reverse-proxy headers by default

Gitea Docker image versions up to and including 1.26.2 use REVERSE_PROXY_TRUSTED_PROXIES=* by default, allowing any source IP to impersonate a user when reverse-proxy authentication headers such as X-WEBAUTH-USER are enabled.

Gitea Affected
Gitea Open Source Git Server
Through 1.26.2
View vendor advisory (opens in new tab)
Published
03 Jul 2026
Exploitation Reported
20 Oct 2026
Attack vector
Remote
Complexity
Low
Privileges
None
User interaction
None

Tags

nuclei_scanner

CVE References

Exploitation evidence

Why Previdian marks this CVE as exploited

Third-party attestation and first-party sensor observation are shown separately so teams can judge the evidence chain.

Exploited in the wild

Previdian

Recorded 20 Oct 2026

Previdian independently recorded this as exploited after first seeing it in honeypot sensors.

Active exploitation observed

Previdian sensor

First observed 20 Oct 2026

Previdian first observed exploitation attempts targeting this vulnerability in our honeypot sensors.

Proof of concept available

GitHub

Recorded 02 Jul 2026

Public scanner or PoC coverage increases practical exploitability.

Known exploited vulnerability sources

Per-source evidence links for KEV attestations are available through the Previdian Pro API.

Learn about Pro API access
Source Added
Previdian Sensors First 2026-10-20 10:05 UTC

Operational indicators for this CVE are listed under Detection.

Sensor telemetry

First-party evidence of exploitation activity

Previdian sensors recorded exploitation attempts targeting this vulnerability. The cards and chart show volume, unique attackers, and daily activity.

64

Attempts observed

4

Unique attacker IPs

4

Attacker countries

AE · DE · IE · NL

3

Sensors observed

CVE-2026-20896 exploitation attempts over the last 7 days

Daily events observed by Previdian sensors

Updated 22 Oct 2026

0
0
0
0
58
6
0
16 Oct 17 Oct 18 Oct 19 Oct 20 Oct 21 Oct 22 Oct

First observed 20 Oct 2026 · Last observed 21 Oct 2026

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Detection

Operational artifacts and observed signals

Make the evidence actionable in scanner, SOC, and edge-control workflows.

Observed signals

Request targets
User-Agents
Callback hosts
29
6
0

Request targets and User-Agents available in Pro. Callback host details available in Enterprise.

Virtual patch status

No Previdian virtual patch is currently available. Future rules ship for ModSecurity, Cloudflare, and AWS WAF.

Learn about virtual patches →

Attacker IP Indicators

Attacker IP indicators observed · available in Pro and Enterprise.

Sensor-derived attacker IP indicators are available to Pro and Enterprise accounts under Detection and through the Pro API.

Learn about Pro API access

Scanner Artifacts

Scanner and exploit-framework references linked to this CVE.

Scanner Reference Detected
Nuclei https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2026/CVE-2026-20896.yaml 19 Aug 2026

Risk and context

Severity, weaknesses, and research context

CVSS v3.1

9.8 Critical

Potential damage if exploited. Separate from whether attackers are using it.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS

2.8%

Estimated chance of exploitation in the next 30 days. Previdian's warning comes from evidence, not this score.

Weaknesses

Improper Access Control CWE-284

Recent mention · The Hacker News

Threat Actors Probe Gitea Docker Flaw CVE-2026-20896 13 Days After Disclosure

Threat actors have been observed attempting to exploit a recently patched critical security flaw in Gitea Docker images, according to Sysdig. The vulnerability in question is CVE-2026-20896 (CVSS score: 9.8), a vulnerability that stems from the DevOps platform trusting the...

Read full advisory

Potential Proof of Concepts

These PoCs are unverified and could contain malware. Use at your own risk.

Raincombat/CVE-2026-20896-Gitea-CTF

github · Created 2026-10-15 09:49:48 UTC · 0 stars · AI assessment 84%

CVE-2026-20896 Gitea Docker CTF Challenge

judgedbykira/CVE-2026-20896-Gitea-Authentication-Bypass

github · Created 2026-08-15 19:01:05 UTC · 0 stars · AI assessment 90%

An explanation and PoC to exploit CVE-2026-20896 Authentication Bypass Vulnerability on Gitea. Being able to steal session tokens for valid users in the Gitea instance.

Gitea Docker Image <= 1.26.2 - Reverse Proxy Header Authentication Bypass

nuclei · Created Unknown

Timeline

From disclosure to observed exploitation

  1. 03:37 UTC

    Indicators of compromise added (4)

    Indicators of compromise recorded

  2. 03:37 UTC

    Observed by Previdian sensors

    Evidence-backed exploitation signal

  3. 04:30 UTC

    Nuclei template available

    Scanner coverage available

  4. 19:01 UTC

    Public PoC available

    Public proof-of-concept code published

  5. 20:19 UTC

    CVE published

    Vulnerability disclosed publicly

  6. 03:25 UTC

    CVE ID reserved

    Identifier reserved by the CNA

Pro API

Automate this intelligence

Confidence, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.

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  • Evidence confidence and provenance
  • First-party sensor telemetry
  • PoC and scanner references
  • Affected versions and enrichment
  • Automation-ready JSON delivery

GET /api/v2/pro/kevs/CVE-2026-20896

Sample API response 
{
  "cve_id": "CVE-2026-20896",
  "confidence": "Confirmed",
  "cvss_score": 9.8,
  "cvss_estimated": false,
  "epss_score": 0.02755,
  "exploit_status": {
    "exploited_in_the_wild": true,
    "active_exploitation_observed": true
  },
  "sensor_telemetry": { "attempts": 64, "sensors": 3 }
}