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CVE-2026-20896

CRITICAL 9.8 PoC CATALOGUED DETECTION TEMPLATE ALL-YEARS

Published 2026-07-03 · Last modified 2026-07-07 · Gitea · NVD: Deferred

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.

REPORTED EXPLOITATION

VulnCheck KEV reports exploitation for this CVE. These are source-specific reports; review the details and vendor guidance below.

Exploitation likelihood

2.8%chance of exploitation in 30 days · 86th percentile

○ In CISA KEV● Catalogued PoC◆ SSVC: exploitation poc, automatable yes

Impact if exploited

9.8CVSS 3.1 · CRITICAL · CNA

  • ConfidentialityHigh
  • IntegrityHigh
  • AvailabilityHigh

What an attacker needs

  • ✓Access: Reachable over the network — no local access needed
  • ✓Privileges: No account or privileges required
  • ✓User interaction: No user interaction needed
  • ✓Complexity: No special conditions — reliably repeatable

✓ lowers the bar for an attacker · ⚠ raises it

Proof of concept

Public PoC or exploit resources are catalogued below.

Listed by the named source; Vulnpedia has not tested these resources.

PoC data: JSON

Detection templates

Detection checks are listed separately from PoCs.

Resource commands

nuclei -id CVE-2026-20896 -u https://TARGETDetection template — review its checks and affected versions before use.
curl -s https://vulnpedia.com/cve/CVE-2026-20896/poc.jsonMachine-readable PoC index for this CVE (for automation).

Search for new PoCs

Search GitHub now — results may be empty or unverified.

Tracked sources are checked weekly for the full archive, including PoCs published after the original disclosure. A later release appears after a tracked source lists it and a refresh succeeds.

Data snapshot:

Affected

Vendors Gitea

Products Gitea Open Source Git Server

Weakness (CWE)

  • CWE-284: Improper Access Control

CVSS vector

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

References and research data (JSON)

Packages and version ranges

Each advisory describes its own package and affected ranges. A boundary applies to that range; it is not a universal upgrade recommendation.

  • code.gitea.io/gitea Go

    pkg:golang/code.gitea.io/gitea

    SEMVER range
    • All earlier versions (introduced 0)
    • Fixed boundary (excluded): 1.26.3
    Additional upstream package constraints
    {
  "database": {
    "source": "https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/07/GHSA-f75j-4cw6-rmx4/GHSA-f75j-4cw6-rmx4.json"
  }
}
    GitHub Advisory Database · GHSA-f75j-4cw6-rmx4 · Updated 2026-07-22T21:11:39.289604207Z
  • code.gitea.io/gitea Go

    pkg:golang/code.gitea.io/gitea

    SEMVER range
    • All earlier versions (introduced 0)
    • Fixed boundary (excluded): 1.26.3
    Additional upstream package constraints
    {
  "ecosystem": {},
  "database": {
    "source": "https://vuln.go.dev/ID/GO-2026-6051.json"
  }
}
    Go Vulnerability Database · GO-2026-6051 · Updated 2026-07-22T21:00:28.336016287Z

Unverified PoC candidates

Catalogue matches for further research. These repositories have not been validated as working exploits.

8 candidates

Additional exploitation reports

Source-specific reports, separate from CISA KEV. Repeated observations from one source are not independent confirmations.

All CVSS metrics

  • CRITICAL 9.8 v3.1 · CNA Primary
    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
  • CRITICAL 9.8 v3.1 · NVD Secondary
    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

References

Exploit-tagged references (not proof of a PoC)

Patches & mitigations

Advisories

Technical & other

Sources: NVD · CVE.org · All sources and attribution · EPSS